To assess the effects of resuscitation with oxygen or room air on the cardiac circulation and the activity of superoxide dismutase (SOD) in a hypoxic newborn piglet model. Methods Newborn piglets(1.6-2.5 kg) were randomly assigned into three groups:control group (n=8) with no hypoxic insult;room air group (n=12) resuscitated with room air for 240 min after 120 min hypoxia;and oxygen group (n=12) resuscitated with 100% oxygen for 30 min followed by 210 min with room air after 120 min hypoxia. Blood gas analysis, blood pressure and hemodynamic parameters were recorded at 0, 10, 30, 60, 120, 180 and 240 min of resuscitation. The activity of superoxide dismutase (SOD) in the left ventricle was measured at 240 min of resuscitation using enzyme method . One-way analysis of variance, two-way analysis of variance measured repeatedly and Student-Newman-Keuls test were applied as statistical methods. Results Severe metabolic acidosis, hypotension and hypoxemia were caused by hypoxia.(1)Arterial oxygen partial pressure(PaO2):At 10 min of resuscitation, PaO2 of control group, room air group and oxygen group was (67±4), (78±12) and (409±42)mmHg(1 mmHg=0.133 kPa) (F=580.19, P<0.01). At 30 min of resuscitation, PaO2 of the three group was (68±3), (79±15) and (342±62)mmHg(F=173.67;P<0.01). PaO2 of oxygen group was higher than room air group and control group (10 min:q=42.51 and 39.28, 30 min: q=23.17 and 21.67, all P<0.05). There was no statistical significance between the room air group and control group. (2)Cardiac output(CO):At 240 min of resuscitation,CO of control group, room air group and oxygen group was(181.6±33.8), (150.9±70.1) and (103.6±53.6) dl/(min·kg) (F=4.82, P<0.05). CO of oxygen group was lower than control group (q=4.25,P<0.05). There was no statistical significance between oxygen group and room air group, neither was between room air group and control group (all P>0.05). (3)Arterial oxygen content (CaO2):At 10 min of resuscitation, CaO2 of control group, room air group and oxygen group was(87.0±16.1), (76.9±13.2) and (102.2±15.9) ml O2/dl (F=8.64, P<0.01). At 30 min of resuscitation, CaO2 of the three group was(87.5±14.9), (79.9±11.3) and (100.1±16.7) ml O2/dl (F=5.98, P<0.01). At 10 min of resuscitation, CaO2 of oxygen group was higher than control group and room air group (q=3.14 and 5.85, all P<0.05). At 30 min of resuscitation, CaO2 of oxygen group was higher than room air group (q=4.85, P<0.01), but there was no statistical significance between oxygen group and control group (q=2.71, P>0.05). (4)Oxygen delivery (DO2): At 10, 30, 60, 120, 180 and 240 min of resuscitation, there were no statistical significance among DO2 of control group, room air group and oxygen group [10 min:(16.5±3.3), (15.7±9.9) and (16.9±4.2)L O2/(kg·min), F=0.10;30 min:(16.2±4.1), (15.1±5.5) and (14.5±3.3) L O2/(kg·min), F=0.38;60 min:(16.1±4.2), (14.9±4.0)and(13.3±3.8)L O2/(kg·min), F=1.28;120 min:(15.5±3.7),(15.6±6.1)and(13.4± 4.6) L O2/(kg·min), F=0.66;180 min:(15.4±3.1), (15.3±9.3) and (11.9±5.0) L O2/(kg·min), F=0.97;240 min:(14.7±3.4), (13.4±6.7) and (9.3±5.2) L O2/(kg·min), F=2.84;all P>0.05]. (5) SOD activity in the left ventricle:At 240 min of resuscitation, SOD activity of control group (n=6), room air group (n=8) and oxygen group (n=8) was (289±107), (210±75) and (142±61)U/mg protein, F=5.75, P<0.05]. SOD activity of oxygen group was lower than control group (q=4.79, P<0.01). There was no statistical significance between oxygen group and room air group, neither was between room air group and control group(q=2.58 and 2.39, all P>0.05). Conclusions Despite higher oxygen content in the blood, resuscitation with oxygen is not beneficial to recovery from metabolic acidosis in newborn hypoxic piglets. Oxygen supplementation does not increase oxygen delivery but reduces SV compared to resuscitation with room air. Resuscitation with oxygen may impair the oxidative stress defense.

Objective To investigate the hemodynamic changes and their association with the expression of β 1 and β 2 adrenoceptors after hypoxia-reoxygenation injury in a neonatal swine model of asphyxia.Methods One to four day-old piglets were randomly assigned to control group (n=6),acute hypoxia group (n=8) and subacute hypoxia group (n=8).The piglets in the control group were observed for 50 h under normoxic mechanical ventilation; while the acute and subacute hypoxia groups were subject to two hours of hypoxic injury induced by ventilation with 0.10-0.15 oxygen followed by 4 or 48 h of observation under normoxic mechanical ventilation,respectively.Blood gases were analyzed and the mean arterial blood pressure,heart rate,and cardiac output were recorded at different time points during the experiment.Tissues from the left ventricle were also harvested to assay lactate,glutathione and β adrenoceptors at the end of the experiment.Analysis of variance,the Tukey test and Pearson correlation analysis were used for statistical analysis of the data.Results Two hours after hypoxia,pH,HCO3-and partial pressure of oxygens (PO2) in the acute hypoxia group and subacute hypoxia group were lower than in the control group,however,pH and HCO3-in animals in the subacute hypoxia group recovered to 7.38 ± 0.05 and (23.04± 2.40)mmol/L,respectively,after reoxygenation,which was similar to those in the control group,and higher than in the acute hypoxia group [7.25±0.07 and (16.88±2.40) mmol/L,respectively,q=6.76 and 7.81,both P＜0.01].Mean arterial pressure,cardiac output and stroke volume in the acute group and subacute group were lower than those in the control animals following two hours of hypoxic injury (all P＜0.01).After reoxygenation,the mean arterial pressure in the acute hypoxia group and subacute group recovered to (42.17±6.14) and (43.19± 5.55) mmHg (1 mmHg=0.133 kPa),cardiac output recovered to (150.04± 56.17) and (169.75 ± 37.85) dl/min,respectively,and there were no differences compared with the control group (all P＞0.05).Expressions of β 1 and β 2 adrenoceptors in the left ventricle in the subacute hypoxia group (1.51 ±0.51 and 2.14±0.66,respectively),were higher than those in the control group (0.56±0.24 and 0.38±0.21,q=7.02 and 10.97,both P＜0.01) and the acute hypoxia group (0.65±0.20 and 0.45±0.11,q=6.86 and 11.38,both P＜0.01).The lactate level in the acute hypoxia group and subacute hypoxia group was higher than that in the control group [(6.95±0.32) and (6.92±0.40) vs (5.03±0.19) μ mol/mg protein,respectively,q=15.43 and 15.19,both P＜0.01].The level of glutathione in the subacute hypoxia group was lower than the control group and acute hypoxia group [(352.00± 16.51) vs (438.35±33.66) and (464.66±52.65) nmol/mg protein,respectively,q=6.00 and 8.46,both P＜0.01).In the subacute hypoxia group,the expressions of β 1 and β 2 adrenoceptors were negatively correlated with the changes in cardiac output (r=-0.60 and-0.59,respectively,both P＜0.05).Conclusions Severe metabolic acidosis and cardiac dysfunction resulting from perinatal asphyxia may recover after reoxygenation,which may be associated with the enhanced expression of β adrenoceptors in the left ventricle during the subacute phase.

Ethylene regulates sex expression in cucumber plants (Cucumis sativus L.). ACC synthase is a key factor during the ethylene biosynthesis. Pairs of PCR primers were synthesized corresponding to the conserved sequences of ACC synthase gene family. The 1 188 bp DNA fragment of ACC synthase gene (CS-ACS2) was amplified from genomic DNA of 8 different sexual phenotypes of cucumber respectively (GenBank accession number is DQ115884～DQ115886 and DQ115875～DQ115879). 8 SNPs have been identified by sequences analysis between 3 monoecious lines and 5 subgynoecious lines and gynoecious lines, which including 4 A←→G and 4 T←→C transition. Of these 8 SNPs, one locus is in intron and 7 loci in exons. Of the 7 SNPs located in exons, 3 SNPs are non-coding SNPs and 4 SNPs are coding SNPs (cSNPs) of which 3 induced changes of encoding amino acid of ACC synthase. The results of SNPs from subgynoecious lines and gynoecious lines suggest that single nucleotide mutation events of CS-ACS2 might be correlated with the development of subgynoecious lines and gynoecious lines in cucumber. Furthermore, CAPS marker C-MT705 was developed for identifying elite subgynoecious cultivar MT-705, which could be valuable in cucumber breeding. Besides, the SNPs and CAPS markers obtained in the study enriched molecular markers of cucumber.

Objective To study the perinatal outcomes of monochorionic diamnionic ( MCDA ) twins.Method A retrospective study had been conducted to analyze the outcomes of MCDA twins delivered in Hospital from Jan 2011 to Dec 2012.According to whether complicated with twin to twin transfusion syndrome ( TTTS, n=14 ) and/or selective intrauterine growth restriction ( sIUGR, n=41 ) , the infants enrolled in the study were assigned into complicated group (n=55) and uncomplicated group (n=90).The infants with sIUGR were further subdivided into three groups .The outcomes of the neonates were compared between the groups.Result A total of 145 pairs of MCDA twins were delivered , 285 neonates (12 of them died after birth ) and 5 cases of stillbirth. The gestational age at delivery in complicated group were significantly lower than those in uncomplicated group (33.8 ±2.8weeks vs.35.5 ±1.6weeks, P<0.001);The birth weight in complicated group ( the birth weight of the bigger baby was 2072 ±460 g vs.2520 ± 383 g, the smaller one 1620 ±477 g vs.2320 ±373 g ) were significantly lighter than those in uncomplicated group;The incidence of fetal death in complicated MCDA twin pregnancies (7.3% vs.0) was significantly higher than controls .Neonatal outcomes of fetuses complicated with sIUGRⅠ ( n=23 ) were similar to controls.Neonates complicated with TTTS, sIUGRⅡ(n =6) or sIUGRⅢ (n =12) had significantly increased incidence of respiratory distress syndrome , asphyxia, cardiac disorders, retinopathy of prematurity and neonatal death compared with controls .Conclusion Neonates of MCDA with TTTS or sIUGR had more complications compared with uncomplicated MCDA twins .The fetuses with abnormal umbilical artery Doppler blood flow are more vulnerable to stillbirth , neonatal death and other serious adverse outcomes .

Objective:To investigate the effects of hypertensive disorders during pregnancy (HDP) on preterm newborns in terms of umbilical cord blood serum ferritin (SF), hemoglobin (Hb) at birth and outcome.Methods:Among inpatients of the First Maternity and Infant Health Hospital Affiliated to Tongji University from October 1, 2015 to December 31, 2016, totally 1 419 cases of preterm newborns were prospectively collected.Preterm infants whose mothers with diagnosis of HDP were recruited as the HDP group.Meanwhile, premature newborns whose mothers without HDP were recruited as the control group.Umbilical cord blood SF levels, Hb levels at birth, outcome of preterm newborns and the basic information for maternity were compared between the two groups.The data of normal distribution between the two groups were compared by independent sample t test.The count data was tested by χ2, and the count data with frequency <5 was tested by Fisher′ s exact test. Results:SF levels of HDP group were significantly lower than the control group [(85.6±67.2) μg/L vs. (103.9±95.5) μg/L]. But Hb levels of HDP group were much higher than the control group [(206.2±33.8) g/L vs. (193.2±31.9) g/L]. The difference between two groups was statistically significant ( t=2.791, 4.825 all P<0.05). Umbilical cord blood SF levels were negatively correlated with Hb levels at birth ( r=-0.120, P<0.001). Moreover, compared to the control group, statistically significant lower incidence of neonatal respiratory distress syndrome (NRDS), pneumonia and bronchopulmonary dysplasia (BPD) in HDP group was observed (all P<0.05). Conclusions:HDP was correlated with umbilical cord blood SF levels and Hb levels at birth in premature newborns.Higher Hb levels and relatively lower incidences of NRDS, pneumonia and BPD were observed in these newborns delivered by mothers with diagnosis of HDP.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.