Objective:To assess the impact of caudal regional anesthesia on complications after hypospadias repair with tubularised incised plate urethroplasty (TIP).Methods:A total of 125 cases with hypospadias undergoing TIP surgery from June 2017 to June 2019 at Beijing Children′s Hospital, Capital Medical University, were reviewed, aged 12-75 months, American Society of Anesthesiologists Ⅰ orⅡ grade.Totally, 86 cases had distal and 39 cases suffered from proximal hypospadias.Caudal anesthetics were used in 42 cases (caudal anesthesia group) and general anesthetics were used in 83 cases (general anesthesia group). All cases were repaired by TIP procedure.The children with urethral fistula and urethral stricture were followed up for 6 months, and multivariate statistical analyses were performed.Results:There were 11 cases of urethral fistula after hypospadias surgery, with 8 cases (9.64%)in the general anesthesia group and 3 cases (7.14%) in the caudal anesthesia group.There were no significant differences between the 2 groups ( χ2=0.223, P=0.636), and 12 cases of urethral stricture, with 8 cases(9.64%) in the general anesthesia group and 4 cases(9.52%) in the caudal anesthesia group.There were no significant differences between the 2 groups ( χ2=0.001, P=0.984). Based on multivariable Logistic regression, urethral fistula was associated with proximal hypospadias ( OR=0.036, 95% CI: 0.003-0.511, P=0.014), and the width of glans( OR=0.469, 95% CI: 0.220-0.998, P=0.049). Urethral stricture was correlated with proximal hypospadias( OR=0.004, 95% CI: 0.000-0.146, P=0.002), the width of urethral plate( OR=0.004, 95% CI: 0.000-0.422, P=0.020), and the duration of catheter( OR=72.976, 95% CI: 1.802-2 594.790, P=0.023). Conclusion:Caudal regional anesthesia appears to have no impacts on urethral fistula and stricture after hypospadias repair.

Objective To establish reference values of normal fetal heart conduction time intervals by tissue Doppler imaging(TDI)and pulsed Doppler(PD)echocardiography,and to assess their correlation with gestational-age and fetal heart rate.Methods One hundred and eighty-nine pregnant women underwent detailed echocardiographic examinations.Atrio-ventricular conduction time interval(AV)and the time interval from onset of ventricular contraction to the onset of atrial contraction of next cardiac cycle(VA)were measured by TDI and PD echocardiography.Results TDI-AV was(126.56±15.33)ms(95% CI 124.10～129.03 ms),TDI-VA was(285.22±24.53)ms(95% CI 281.27～289.16 ms),PD-AV was(127.42±12.88)ms(95% CI 125.35～129.49 ms),PD-VA was(287.42±25.19)ms(95% CI 283.37～291.47 ms).A paired t test revealed no systematic difference between the two approaches used to measure AV and VA.AV and VA were significantly positively correlated with gestational age,and significantly negatively correlated with fetal heart rate.Heart conduction time intervals were altered in fetus with paroxysmal arrhythmia.Conclusions This study established the normal values of fetal heart conduction time intervals.Prenatal determination of fetal heart conductional time intervals has important potential clinical utility in assessing fetal arrhythmia.

Objective:To analyze the relationship between renin-angiotensin-aldosterone system (RAAS) gene polymorphisms and susceptibility to essential hypertension (EH) in military secret service personnel.Methods:In October 2019, military secret service personnel (162 people) who were recuperating in a sanatorium from January to December 2017 were selected as the research subjects, all of whom were Han and male. The patients (79 people) who were diagnosed with EH according to the diagnostic criteria of hypertension in the "Chinese Guidelines for the Prevention and Treatment of Hypertension" (2016 Revised Edition) were the case group, and the people with normal blood pressure (83 people) were the control group. Occupational epidemiological investigation was conducted, 5 ml of fasting cubital venous blood was collected, genomic DNA was extracted by phenol-chloroform method, and RAAS gene polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism method. The distribution differences of genotype and allele frequency between groups were compared, and the relationship between genotype, allele frequency and EH was analyzed.Results:The average age of military secret service personnel was (38.2±5.3) years old, and there was no statistical significance in the average age and the age distribution over 40 years old of the case group and the control group ( P>0.05) . There were significant differences in the distribution of AGT gene M235T locus, ACE gene I/D polymorphism genotype and allele between the case group and the control group ( P<0.05) . The TT genotype with AGT gene M235T locus ( OR=3.28, 95% CI: 1.21-8.91) and DD genotype with ACE gene ( OR=2.86, 95% CI: 1.17-7.00) were risk factors for EH in military secret service personnel. Conclusion:The TT genotype of AGT gene M235T and the DD genotype of ACE gene may be the susceptibility genotypes of military secret service personnel for EH.

Objective:To analyze the relationship between renin-angiotensin-aldosterone system (RAAS) gene polymorphisms and susceptibility to essential hypertension (EH) in military secret service personnel.Methods:In October 2019, military secret service personnel (162 people) who were recuperating in a sanatorium from January to December 2017 were selected as the research subjects, all of whom were Han and male. The patients (79 people) who were diagnosed with EH according to the diagnostic criteria of hypertension in the "Chinese Guidelines for the Prevention and Treatment of Hypertension" (2016 Revised Edition) were the case group, and the people with normal blood pressure (83 people) were the control group. Occupational epidemiological investigation was conducted, 5 ml of fasting cubital venous blood was collected, genomic DNA was extracted by phenol-chloroform method, and RAAS gene polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism method. The distribution differences of genotype and allele frequency between groups were compared, and the relationship between genotype, allele frequency and EH was analyzed.Results:The average age of military secret service personnel was (38.2±5.3) years old, and there was no statistical significance in the average age and the age distribution over 40 years old of the case group and the control group ( P>0.05) . There were significant differences in the distribution of AGT gene M235T locus, ACE gene I/D polymorphism genotype and allele between the case group and the control group ( P<0.05) . The TT genotype with AGT gene M235T locus ( OR=3.28, 95% CI: 1.21-8.91) and DD genotype with ACE gene ( OR=2.86, 95% CI: 1.17-7.00) were risk factors for EH in military secret service personnel. Conclusion:The TT genotype of AGT gene M235T and the DD genotype of ACE gene may be the susceptibility genotypes of military secret service personnel for EH.

L-glutamic acid is the world's largest bulk amino acid product that is widely used in the food, pharmaceutical and chemical industries. Using Corynebacterium glutamicum G01 as the starting strain, the fermentation by-product alanine content was firstly reduced by knocking out the gene encoding alanine aminotransferase (alaT), a major by-product related to alanine synthesis. Secondly, since the α-ketoglutarate node carbon flow plays an important role in glutamate synthesis, the ribosome-binding site (RBS) sequence optimization was used to reduce the activity of α-ketoglutarate dehydrogenase and enhance the glutamate anabolic flow. The endogenous conversion of α-ketoglutarate to glutamate was also enhanced by screening different glutamate dehydrogenase. Subsequently, the glutamate transporter was rationally desgined to improve the glutamate efflux capacity. Finally, the fermentation conditions of the strain constructed using the above strategy were optimized in 5 L fermenters by a gradient temperature increase combined with a batch replenishment strategy. The glutamic acid production reached (135.33±4.68) g/L, which was 41.2% higher than that of the original strain (96.53±2.32) g/L. The yield was 55.8%, which was 11.6% higher than that of the original strain (44.2%). The combined strategy improved the titer and the yield of glutamic acid, which provides a reference for the metabolic modification of glutamic acid producing strains.
Glutamic Acid ; Corynebacterium glutamicum/genetics* ; Ketoglutaric Acids ; Metabolic Engineering ; Alanine

Glutamic acid is an important amino acid with wide range of applications and huge market demand. Therefore, by performing transcriptome sequencing and re-sequencing analysis on Corynebacterium glutamicum E01 and high glutamate-producing strain C. glutamicum G01, we identified and selected genes with significant differences in transcription and gene levels in the central metabolic pathway that may have greatly influenced glutamate synthesis and further increased glutamic acid yield. The oxaloacetate node and α-ketoglutarate node play an important role in glutamate synthesis. The oxaloacetate node and α-ketoglutarate node were studied to explore effect on glutamate production. Based on the integrated strain constructed from the above experimental results, the growth rate in a 5-L fermenter was slightly lower than that of the original strain, but the glutamic acid yield after 48 h reached (136.1±5.53) g/L, higher than the original strain (93.53±4.52) g/L, an increase by 45.5%; sugar-acid conversion rate reached 58.9%, an increase of 13.7% compared to 45.2% of the original strain. The application of the above experimental strategy improved the glutamic acid yield and the sugar-acid conversion rate, and provided a theoretical basis for the metabolic engineering of Corynebacterium glutamicum.
Citric Acid Cycle ; Corynebacterium glutamicum/metabolism* ; Glutamic Acid/metabolism* ; Metabolic Engineering ; Metabolic Networks and Pathways/genetics*

γ-aminobutyric acid can be produced by a one-step enzymatic reaction catalyzed by glutamic acid decarboxylase. The reaction system is simple and environmentally friendly. However, the majority of GAD enzymes catalyze the reaction under acidic pH at a relatively narrow range. Thus, inorganic salts are usually needed to maintain the optimal catalytic environment, which adds additional components to the reaction system. In addition, the pH of solution will gradually rise along with the production of γ-aminobutyric acid, which is not conducive for GAD to function continuously. In this study, we cloned the glutamate decarboxylase LpGAD from a Lactobacillus plantarum capable of efficiently producing γ-aminobutyric acid, and rationally engineered the catalytic pH range of LpGAD based on surface charge. A triple point mutant LpGAD^{S24R/D88R/Y309K} was obtained from different combinations of 9 point mutations. The enzyme activity at pH 6.0 was 1.68 times of that of the wild type, suggesting the catalytic pH range of the mutant was widened, and the possible mechanism underpinning this increase was discussed through kinetic simulation. Furthermore, we overexpressed the Lpgad and Lpgad^{S24R/D88R/Y309K} genes in Corynebacterium glutamicum E01 and optimized the transformation conditions. An optimized whole cell transformation process was conducted under 40 ℃, cell mass (OD₆₀₀) 20, 100 g/L l-glutamic acid substrate and 100 μmol/L pyridoxal 5-phosphate. The γ-aminobutyric acid titer of the recombinant strain reached 402.8 g/L in a fed-batch reaction carried out in a 5 L fermenter without adjusting pH, which was 1.63 times higher than that of the control. This study expanded the catalytic pH range of and increased the enzyme activity of LpGAD. The improved production efficiency of γ-aminobutyric acid may facilitate its large-scale production.
Glutamate Decarboxylase/genetics* ; Lactobacillus plantarum/genetics* ; Catalysis ; gamma-Aminobutyric Acid ; Hydrogen-Ion Concentration ; Glutamic Acid

Background A large amount of iron deposition in the brain can cause neuronal damage by inducing oxidative stress, neuroinflammation, and abnormal mitochondrial function. In addition, iron deposition is also reported to be closely related to the pathogenesis of Alzheimer's disease (AD). The neurofibrillary tangles aggregated by tau hyperphosphorylation are one of the important pathological features of AD. Objective To investigate potential effect of exogenous trivalent iron ions on neuronal activity in human neuroblastoma (SH-SY5Y) cells and tau hyperphosphorylation and aggregation. Methods SH-SY5Y cells were treated with ferric chloride (FeCl₃) at four concentrations (10, 100, 200, and 400 mg·L⁻¹). Cell survival rate was then detected by CCK8 assay. Intracellular iron content was determined prussian blue (Perl's) by iron staining after 24 h exposure to FeCl₃ at 10 or 200 mg·L⁻¹. Transfection of tau-P301L plasmid was conducted to construct an AD-like cell model for tau overexpression. The differences in the expression of the phosphorylated tau (p-tau) protein in SH-SY5Y cells and SH-SY5Y cells with tau overexpression were detected by Western blotting after 24 h exposure to FeCl₃ at 10 and 200 mg·L⁻¹. After dilution with phosphate buffered saline (PBS), FeCl₃, human tauR3, and FeCl₃ + tauR3 were incubated at 37℃, and the fluorescence intensity reflecting tau aggregation level was measured by thioflavin T(ThT) method at 12, 24, 36, 48, 60, 72, 84, and 96 h, respectively. Meanwhile, after 96 h coincubation of FeCl₃ and tauR3, the fibers formed by tau aggregation were observed under a transmission electron microscope (TEM). Results After 24 h of FeCl₃ exposure, the cell survival rate of SH-SY5Y cells among all groups was statistically different (F=8.63, P<0.01). The cell survival rates in the 200 and 400 mg·L⁻¹ groups were 80.1% and 68.7% of the control group, respectively (P<0.05). Compared with the control group, the nuclei of the 200 mg·L⁻¹ FeCl₃ group were mainly yellowish-brown after iron staining and the positive cell rate was up-regulated by 12.9% (P<0.01). After 24 h of FeCl₃ exposure , the p-tau (Ser396) protein expression was statistically different among all groups (F=11.6, P<0.01). Compared with the control group, the p-tau protein expression level of SH-SY5Y cells in the 200 mg·L⁻¹ group was up-regulated by 72.7% (P<0.01). After FeCl₃-treated SH-SY5Y cells with tau overexpression for 24 h, the p-tau (Ser396) protein expression was statistically different among all groups (F=27.8, P<0.01). Compared with the tau group, the p-tau (Ser396) protein expression level of SH-SY5Y cells in the tau + 200 mg·L⁻¹ group was up-regulated by 44.6% (P<0.05). Compared with the tauR3 group, the fluorescence intensities in the 84 and 96 h tauR3 + FeCl₃ groups were up-regulated by 49.9% and 53.7% (P<0.01) respectively. After 96 h of coincubation, compared with the tauR3 group, FeCl₃ + tauR3 aggravated tau aggregation and formed fiber deposition under TEM. Conclusion Exogenous trivalent iron ions may inhibit SH-SY5Y cell viability, promote the phosphorylation of tau in SH-SY5Y cells transfected with tau-P301L plasmid, and aggravate tauR3 aggregation and fiber production.