1.Expression and enzymatic properties of urate oxidase from Candida utilis in Lactococcus lactis
Chinese Journal of Biologicals 2025;38(05):543-548+556
Objective To express urate oxidase(UOX) from Candida utilis in lactic acid bacteria and study its enzymaticproperties, so as to provide technical supports for the application and development of UOX.MethodsThe optimized UOXgene was synthesized and cloned into the vector pTRKH2 to construct the recombinant expression plasmid, which was thenelectroporated to competent Lactococcus lactis NZ9000 to screen the recombinant strain and express the recombinant UOX(rUOX) with His-tag. Using UOX enzyme activity as an index, the fermentation conditions of recombinant bacteria were opti-mized. The rUOX was purified by nickel ion metal chelate chromatography, and its enzymatic properties were characterized.ResultsThe optimum expression conditions of the recombinant strain were as follows: fermentation temperature 37 ℃,fermentation time 12 h, and initial pH 6 of fermentation medium, respectively, and the rUOX enzyme activity reached(44. 57 ±0. 43) U/mL. The relative molecular mass of purified rUOX was about 35 000, consistent with the theoretical relative molecu-lar mass, and the specific activity was 17. 48 U/mg. The optimum pH and temperature of rUOX were 11. 5 and 45 ℃, andunder the optimal conditions, the K_m, V_(max)and k_(cat)values of rUOX were 5. 72 mmol/L, 71. 25 μmol/(L·min) and 95. 76/s,respectively, with uric acid as the substrate. Various metal ions and chemical reagents had inhibitory activity on rUOX, whileTween 20 exhibited obvious activation activity on rUOX.ConclusionThe recombinant expression of UOX in lactic acidbacteria is feasible, and its enzyme activity is relatively stable, which provides an experimental basis for the development andapplication of UOX under alkali-tolerant conditions.
2.Change of endothelin-1 and nitrogen monoxide in rats with paraquat poisoning.
Chinese Journal of Industrial Hygiene and Occupational Diseases 2008;26(4):242-244
Animals
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Disease Models, Animal
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Endothelin-1
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metabolism
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Male
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Nitric Oxide
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metabolism
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Paraquat
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poisoning
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Rats
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Rats, Sprague-Dawley
3.Analysis of health system responsiveness of Huzhou
Journal of Shanghai Jiaotong University(Medical Science) 2006;0(03):-
Objective To analyse the health system responsiveness of Huzhou of Zhejiang Province. Methods Performance evaluation method proposed by WHO was employed for the study of responsiveness. The local residents of Huzhou of Zhejiang Province in 2007 were investigated with multilevel cluster stratified sampling. Data were obtained by household survey and involved items such as dignity,independence,privacy,communication,timely attention,equipment,social support and selection of medical staff,and were subjected to empirical analysis. Results Household survey was conducted in 1353 residents,among whom 28.16% lived in town and 71.84% lived in countryside. The index of health system responsiveness of Huzhou was 7.96,slightly higher than that of Zhejiang Province (7.71). The responsiveness was significantly higher for countryside than that for town in independence,communication and timely attention (P
4.Characteristics and selection of intraocular lens
Ping LIU ; Guangsen SHI ; Zhijian LI
Ophthalmology in China 1994;0(02):-
With the rapid development in cataract operation,characteristics and types of intraocular lens have been improving and altering all along in over fifty years.The correct selection for intraocular lens is significant for cataract patient to get better vision after operation.Description of characteristics and selection of the intraocular lens are summarized.
5.Histological chorioamnionitis in placenta and preterm birth
Ying WANG ; Ping LIU ; Chunyan SHI
Chinese Journal of Perinatal Medicine 2015;18(8):606-609
Objective To investigate the causes and mechanism of preterm birth through analysis of the relationship between histological chorioamnionitis (HCA) in placental tissue and preterm birth.Methods Totally,327 preterm birth cases with report of placental pathologic examination were retrospectively collected from those women who delivered from December 1,2009 to December 1,2012 in Peking University First Hospital.According to the etiology of preterm birth,three groups were assigned:iatrogenic group (n=106),spontaneous contraction group (n=56) and premature rupture of membranes (PROM) group (n=165).According to the gestational age at delivery,three subgroups were further divided:early-preterm group (≥ 28-< 32 weeks),mid-preterm group(≥ 32-< 34 weeks) and late-preterm group (≥ 34-< 37 weeks).HCA was confirmed when ≥ 5 neutrophil infiltration identified on the chorionic plate and amniotic membrane under high power light microscope after HE staining.The relationship between HCA and the different types of preterm birth and the different delivery gestational age were analyzed.Besides,the consistency between clinical chorioamnionitis and HCA was also analyzed.Chi-square test was applied for statistics.Results The incidence of HCA in the spontaneous contraction group was significantly higher than in the iatrogenic group and PROM group [66.1% (37/56) vs 25.5% (27/106) and 33.3% (55/165),x2=25.27 and 18.44,both P < 0.01],but no significant difference was found between the latter two groups (P > 0.05).Among the three subgroups,the early-,midand late-preterm subgroup,the incidence of HCA in the iatrogenic group was 24.0% (6/25),33.3% (8/24) and 22.8% (13/57) (P > 0.05),and 13/17,5/7 and 59.4% (19/32) in the spontaneous contraction group (P > 0.05).However,significantly higher incidence of HCA was shown in the early-preterm subgroup than in the mid-and late-preterm subgroup [70.0% (20/29) vs 41.2% (14/34) and 20.6% (21/102),X2=4.87 and 24.58,both P < 0.05] in the PROM group.Among the subjects in PROM group,those with the latency ≥ 72 h after the rupture of membranes had a higher incidence of HCA than those with the latency less than 72 h [68.6% (24/35) vs 23.8% (31/130),x2=24.82,P < 0.01].For all 327 cases in this study,the incidence of clinical chorioamnionitis was 15.9% (52/327),among which 31 cases [59.6% (31/52)] were diagnosed as HCA.Conclusions The occurrence of HCA is closely associated with spontaneous contraction preterm.Some iatrogenic preterm birth might cause HCA.The earlier the preterm birth and the longer the latency after PROM,the higher the incidence of HCA.Differential diagnosis is necessary as the inconsistency between clinical chorioamnionitis and HCA.
6.Analysis on brain targeting of scopolamine following intranasal administration by using solid phase extraction and LC/MS assay
Ping LI ; Huafen WANG ; Weifeng SHI ; Lanlan LIU ; Wei LIU
Chongqing Medicine 2013;(36):4405-4407
Objective To investigate the distribution of scopolamine into brain following intranasal .Methods Adult Wistar rats were divided into two groups ,and administrated with scopolamine 0 .3 mg via intraperitoneal or intranasal respectively .Two groups of blood concentration and brain concentration of scopolamine were determined by solid phase extraction (SPE) and LC/MS assay at the time point of 5 ,10 ,20 ,30 ,60 ,120 ,240 ,480 min ,and their kinetic parameters were calculated and compared .Results Scopol-amine bioavailability of intranasal administration was 65% ,and the maximum concentration of scopolamine in brain following in-tranasal administration was much higher than that following intraperitoneal administration .Comparing the ratio of AUC in brain and in plasma ,ratio of intranasal administration is bigger than that of intraperitoneal administration significantly (P<0 .05) .Con-clusion It was concluded that scopolamine′s intranasal administration induced the agent targeting distribution into the brain .
7.Two cases of pulmonary thromboembolism associated with protein C and protein S deifciency and literature review
Fang LIU ; Lanyan ZHU ; Ping CHEN ; Zhihui SHI ; Shaokun LIU
Journal of Central South University(Medical Sciences) 2013;38(9):971-976
To explore the clinical manifestations, diagnosis and treatment of pulmonary thromboembolism associated with protein C (PC)/protein S (PS) deifciency. Two male patients 29 and 26 years old diagnosed with PC deifciency and/or PS deifciency were retrospectively analyzed and related literatures were reviewed. The most common symptoms were pain in the lower limbs with chest pain or decreased vision. Color dopper lfow imaging (CDFI) showed lower deep venous phlebothrombosis. Multislice CT angiography (CTA) revealed pulmonary embolism. The level of serum homocysteine (HCY) increased and the level of plasma PC/PS content decreased to PC 57.4%, and PS 28.9%in patient 1, while PS 33.4%in patient 2. Poor routine anticoagulant response was observed. After the diagnosis of PC/PS deficiency, vitiamin B6 and B12 anticoagulant therapy was added, and the symptoms in the patients improved significantly. Congenital thrombophilia should be taken into consideration for young patients with lower deep venous thrombosis and pulmonary embolism which occur recurrently without obvious predisposing causes before 40. Plasma PC/PS concentrations or activity help a lot in the diagnosis and treatment.
9.Analysis Methods of Short-term Non-linear Heart Rate Variability and Their Application in Clinical Medicine.
Xianglin CHI ; Jianhua ZHOU ; Ping SHI ; Chengyu LIU
Journal of Biomedical Engineering 2016;33(1):193-200
The linear analysis for heart rate variability (HRV), including time domain method, frequency domain method and time-frequency analysis, has reached a lot of consensus. The non-linear analysis has also been widely applied in biomedical and clinical researches. However, for non-linear HRV analysis, especially for short-term non-linear HRV analysis, controversy still exists, and a unified standard and conclusion has not been formed. This paper reviews and discusses three short-term non-linear HRV analysis methods (fractal dimension, entropy and complexity) and their principles, progresses and problems in clinical application in detail, in order to provide a reference for accurate application in clinical medicine.
Electrocardiography
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Entropy
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Fractals
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Heart Rate
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Humans