Cost-utility analysis of tislelizumab monotherapy for second-line treatment of advanced or metastatic esophageal squamous cell carcinoma / 中国药房

OBJECTIVE To evaluate the cost-effectiveness of tislelizumab monotherapy in the second-line treatment of advanced or metastatic esophageal squamous cell carcinoma （ESCC），so as to provide reference for rational use of drug in clinic. METHODS A three-state partitioned survival model was constructed from the perspective of China’s health system， based on the data of RATIONALE-302 study，with simulation time limit of 10 years， cycle period of 1 month. The incremental cost-effectiveness ratio （ICER） was calculated with quality-adjusted life year （QALY） as utility index. The cost-effectiveness of tislelizumab monotherapy was compared with that of chemotherapy for second-line treatment of advanced or metastatic ESCC by cost-utility analysis. The stability of basic analysis results was validated through sensitivity analysis and scenario analysis. RESULTS The results of basic analysis showed that compared with chemotherapy group， incremental cost per capita of tislelizumab group was 35 025.32 yuan，and incremental utility per capita was 2.71 QALYs； ICER was 12 892.31 yuan/QALY， which was far lower than the willingness-to-pay （WTP） threshold of 3 times of China’s per capita gross domestic product （GDP） 242 928 yuan in 2021. The results of univariate sensitivity analysis showed that parameters such as the cost of apatinib， the utility value of disease progression status and the cost of adverse reactions in the chemotherapy group had a great impact on the ICER value， but these parameters could not cause the reversal of the basic analysis results. Probabilistic sensitivity analysis showed that WTP threshold was higher than 80 000 yuan/QALY，the probability of tislelizumab monotherapy possessed cost-effectiveness was 100%. Results of scenario analysis showed that in which model simulation time lasted for 5 or 20 years，ICER of tislelizumab was 8 331.00 yuan/QALY and 12 981.00 yuan/QALY， which were less than 3 times of China’s per capita GDP in 2021 as WTP threshold. CONCLUSIONS When three times of China’s GDP per capita in 2021 is taken as the WTP threshold， the second-line treatment of tirelizumab monotherapy for advanced or metastatic ESCC is more cost-effective than chemotherapy.

Analysis on the application of medical force in Shenzhou manned spaceflight missions and enlightenment for medical service support with new regions and new types / 中华急诊医学杂志

Objective:To summarize the practice and experience of medical service support for Shenzhou manned spaceflight mission, and to explore the accurate medical service support strategy with new regions and new types.Methods:A systematic summary was made from the force command, action framework, technical support, and the practice and experience in the application of medical support force for Shenzhou manned flight mission were sorted out.. Furthermore, the key and difficult problems of the new domains with new types of military medical service support were analyzed, and the scheme and significance of establishing the accurate support mode of the new medical service support force were proposed.Results:The Shenzhou emergency rescue mission was an elite combat supported by a large platform. It was an important basis to realize accurate medical service support by the experience of utilizing the medical force of Shenzhou emergency rescue and the strengthening of war-building mode optimization.Conclusions:This paper systematically summarizes the experience and characteristics of medical force application in Shenzhou manned spaceflight missions, and provides new ideas and methods for future diversified and accurate s medical service support with new regions and new types.

Clinical evaluation of platelet-rich plasma in the treatment of early and middle stage knee osteoarthritis under 3.0T MRI T2 mapping sequence / 中华外科杂志

Objective: To quantitatively evaluate the clinical effect of platelet-rich plasma(PRP) intra-articular injection for early and middle stage knee osteoarthritis(KOA) treatment by 3.0T MRI T2 mapping sequence. Methods: Clinical data of 26 patients with early or middle stage KOA who received treatment from April to December 2021 at Department of Orthopaedic Surgery,the Second Affiliated Hospital,Zhengzhou University were retrospectively analyzed. In total, 8 patients were male and 18 were female,with age of (66.4±12.0)years(range:51 to 94 years). Four patients were bilateral KOA and 22 patients were unilateral KOA.All patients received PRP intra-articular injection. Patients underwent 3.0T MRI T2 mapping sequence scanning pre-treatment,3-month-after and 6-month-after treatment respectively. Those were used to measure and compare T2 values of medial and lateral femoral articular surface and patellofemoral articular surface. Visual analogue scale(VAS) and Western Ontario and McMaster Osteoarthritis Index (WOMAC) score were recorded and evaluated. The results were analyzed using repeated measure ANOVA followed by Bonferroni multiple comparison test.The correlation between WOMAC scores and T2 values at pre-treatment and 6 months post-treatment was analyzed using Pearson correlation test. Results: After treatment, the patients' International Cartilage Regeneration＆Joint Preservation Society(ICRS) classification were partly improved(one case improved from grade Ⅲ to grade Ⅱ, one case improved from grade Ⅱ to grade Ⅰ),and all patients generally improved after treatment in clinical symptoms. Compared with pre-treatment,VAS and WOMAC scores of grade Ⅰ,Ⅱ,and Ⅲ of 6-month after treatment were declined significantly(all P<0.05).The T2 values of articular cartilage declined to varying degrees(the decrease in T2 values was about 2.06 ms in grade Ⅰ, 2.66 ms in grade Ⅱ, and 3.72 ms in grade Ⅲ).Three-month (VAS:4.8±1.3,WOMAC:21.5±4.0) and 6-month (VAS:4.2±1.4,WOMAC:17.2±2.9) after treatment, the VAS and WOMAC score were significantly higher than those before treatment (VAS:6.0±1.2, WOMAC:29.0±2.3) (F=48.846, F=346.746;both P<0.01). Multiple comparisons showed a statistically significant difference between pre-treatment and post-treatment VAS (P<0.01) and it also was significantly different between 3-month and 6-month post-treatment (P<0.01).At 3- and 6-month after treatment,WOMAC scores were significantly different from before treatment.And it also was significantly different between 3-month and 6-month post-treatment (P<0.01).There was a statistically significant improvement in T2 values of patellofemoral articular surface, medial and lateral femoral articular surface at pre-treatment((44.64±4.02)ms,(44.17±3.64)ms and(43.53±3.91)ms) and 3-month ((43.19±3.91)ms,(43.24±3.34)ms and (42.47±3.80)ms), 6-month ((41.49±3.64)ms,(41.83±3.15)ms and (41.10±3.42)ms) after treatment(F=148.845,F=73.657,F=86.268;all P<0.01).The results of the multiple comparisons showed a statistically significant difference in the T2 values of medial and lateral femoral articular surface and patellofemoral articular surface at each time point(all P<0.01).The Pearson correlation analysis suggested that the WOMAC score at pre-treatment was positively correlated with the medial condyle (r=0.856,P<0.01) and the patellofemoral joint surface T2 values (r=0.840,P<0.01);The WOMAC score at 6-month post-treatment was positively correlated with the medial condyle (r=0.731,P<0.01) and the patellofemoral joint surface T2 values (r=0.691,P<0.01). Conclusions: In the treatment of early and mid-stage KOA,MRI T2 mapping sequences are able to indicate the integrity of cartilage morphology and quantitatively evaluate cartilage repair. PRP has a good therapeutic effect on cartilage repair and reconstruction.

Current status of research on circulating microRNAs as diagnostic markers for hepatocellular carcinoma / 临床肝胆病杂志

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, and its high mortality rate is closely associated with the unsatisfactory diagnostic and monitoring methods for HCC at present. Some microRNAs (miRNAs) play an important role in the development and progression of HCC, and their abnormal expression is a common phenomenon in HCC pathology; in addition, miRNAs can be released into the circulating blood and remain stable in blood. By reviewing the research advances in the role of miRNAs in HCC, it is pointed out that miRNAs are expected to become potential markers for the early diagnosis, monitoring and treatment, and prognostic evaluation of HCC, and this article also analyzes related issues in the clinical verification of such potential markers.

Therapeutic effect of Weichangning granule combined with compound Lactobacillus acidophilus tablet in the treatment of diarrhea type irritable bowel syndrome and its effect on inflammatory factors, gastrointestinal hormones and intestinal mucosal barrier / 中国基层医药

Objective:To investigate the therapeutic effect of Weichangning granule combined with compound Lactobacillus acidophilus tablet on diarrhea type irritable bowel syndrome and its effect on inflammatory factors, gastrointestinal hormones and intestinal mucosal barrier.Methods:From January 2017 to December 2019, 80 patients with diarrhea type irritable bowel syndrome admitted in the First People's Hospital of Fuyang District were selected, and they were divided into observation group and control group according to the random digital table method, with 40 cases in each group.The control group was treated with relapsed Lactobacillus acidophilus tablets, and the observation group was treated with Weichangning granules on the basis of the control group.The course of treatment in both two groups was 2 weeks.The changes of inflammatory factors, gastrointestinal hormones and intestinal mucosal barrier were compared before and after treatment.Results:The total effective rate of the observation group[92.50%(37/40)] was higher than that of the control group[70.00%(28/40)], the difference was significant (χ 2=6.646, P<0.05). The levels of TNF-α[(36.15±10.12)ng/L], IL-1β[(0.43±0.08)μg/L] and IL-6[(12.18±3.06)ng/L] in the observation group were lower than those in the control group[(54.36±15.73)ng/L, (0.79±0.12)μg/L and (18.53±2.19)ng/L]( t=6.157, 15.787, 10.673, all P<0.05). The serum levels of SS[(28.91±11.02)μg/L] and VIP[(185.46±17.34)ng/L] in the observation group were lower than those in the control group[(45.63±12.54)μg/L and (235.12±18.29)ng/L]( t=6.334, 12.462, all P<0.05). The levels of DAO[(1.05±0.19)U/L], endotoxin[(0.62±0.19)U/L] and D-lactate[(38.97±6.39)mg/L] in the observation group were lower than those in the control group[(1.53±0.28)U/L, (1.16±0.23)U/L and (49.81±4.25)mg/L]( t=8.972, 11.448, 8.934, all P<0.05). Conclusion:Weichangning granule combined with compound Lactobacillus acidophilus tablet has obviously curative effect on diarrhea type irritable bowel syndrome, which can reduce inflammatory reaction, improve gastrointestinal hormone and intestinal mucosal barrier function.

Dendrobium officinale cliff epiphytic cultivation method / 中国中药杂志

To solve the issues of costly planting of facility cultivation method and inferior efficacy than wild herbs of Dendrobium officinale, the cliff epiphytic cultivation method was studied. To research the growth, agronomic traits, yield, polysaccharide and alcohol-soluble extract contents were measured on the D. officinale from different water regulation and cliff slope gradients treatments. The results showed that D. officinale epiphytic at 85 degrees-90 degrees cliff and sprayed water 1-2 h x d(-1) at the growing season can get better growth and obtain high yield, and the morphology has no different from wild cliff D. officinale, even in the environments without shade. The contents of polysaccharide and alcohol-soluble extract are closely related to the physiological ages, but significantly higher than the facility cultivation. It is possible that environmental stresses benefit the accumulation of polysaccharides, alcohol-soluble extract and other efficient ingredients.

Detection of growth phenotype and blood biochemical parameters of wild type-derived chromosome 1 substitution mouse strain / 中国实验动物学报

Objective To analyze the growth phenotype and blood biochemical parameters of chromosome 1 substi-tution mouse strain(CSS1), and investigate their potential of QTL mapping .Methods Body weight, body length, tail length, organ weight of the CCS1 mice were measured at different days to create a growth curve while blood biochemical in -dexes were measured at about the 80th day.Results The CCS1 mice were different from C57BL/6 mice in several inde-xes.Compared with the C57BL/6 mice during different developmental stages , six strains including B6-Chr1KM mice were significantly different in body weight .There were five strains including B6-Chr1CM mice significantly different with C57BL/6 mice in body length, and all of the CSS1 mice were significantly different from C57BL/6 mice in tail length.Part of CCS1 mice were significantly different from C57BL/6 mice in the weight of liver, spleen, kidney and brain.The ALT of female B6-Chr1CM mice was significantly higher than that in the C 57BL/6 mice.The ALP of female B6-Chr1HZ mice was signifi-cantly higher than that in the male C57BL/6 and B6-Chr1KM mice, and was significantly lower than that in the C57BL/6 mice.The TB of male B6-Chr1CM, B6-Chr1SMX and B6-Chr1HZ mice was significantly higher than that of the C 57BL/6 mice.The TG of male B6-Chr1SMX mice and male B6-Chr1TW mice was significantly higher than that in the C 57BL/6 mice. Conclusions The phenotype of Chr1 CSS mice is quite different from commonly used inbred strain C 57BL/6 mice.CCS1 mice show great potential in QTL mapping for their characteristic growth phenotype and blood biochemical indexes .

Aptamer-Based Microcantilever Sensor for O-ethyl S-[2-(diisopropylamino) ethyl] methylphosphonothiolate, Sarin Detection and Kinetic Analysis / 分析化学

A new method for O-ethyl S-[2-( diisopropylamino) ethyl] methylphosphonothiolate ( VX) , sarin detection and its kinetic analysis based on piezoresistive microcantilever aptasensor was developed, where VX, sarin aptamers were immobilized on the microcantilever surface by biotin-avidin binding system. A linear relationship between the response voltage and the concentration of VX in the range of 2-60μg/L was obtained. The linear regression equation was △Ue=0. 886C-1. 039 (n=5, R=0. 984, p<0. 001) and the detection limit was 2μg/L ( S/N≥3 ) . A linear relationship between the response voltage and the concentration of sarin in the range of 10-60 μg/L was obtained, the linear regression equation was △Ue=0. 716C-2. 304 ( n=5, R=0 . 996 , p<0 . 001 ) and the detection limit was 10 μg/L ( S/N≥3 ) . The sensor showed no response for O-butyl methylphosphonochloridate, a structural analog of VX and sarin, which indicated high specificity and good anti-interference ability. On this basis, a reaction kinetic model based on receptor-ligand binding and the relationship with output voltage change was established. Response voltage (△Ue ) and response time( t0 ) were obtained from the fitting equation on different concentrations of VX, sarin fitted well with the measured values.

Anti-drought differential proteome on interaction between Anoectochilus formosanus and mycorrhizal fungi / 中国药学杂志

OBJECTIVE: To study the proteomic difference between mycorrhizal fungi infected and uninfected plants and then to explore the possible anti-drought mechanism caused by mycorrhizal fungi. METHODS: The differential proteome of Anoectochilus formosanus infected by Rhizoctonia sp. growing in drought was investigated by means of 2D gel electrophoresis. RESULTS: Eight proteins were involved in photosynthesis, among them 7 proteins were correlated with CO2 fixation of darkreaction. Meanwhile, C4 pathway suited in drought condition was mobilized by the plants to utilize CO2 thoroughly. Five proteins were involved in glyoometabolism and li-pometabolism, and 3 in protein synthesis. CONCLUSION: Increased darkreaction of photosynthesis, especially the C4 pathway in infected fungi can enhance the capability of CO2 fixation and utilization when the stoma is closed. The glycometabolism, lipometabolism, protein synthesis, and resistance to pests of the infected plants are also enhanced in drought condition. Fungus of Rhizoctonia sp. can help plants improve their capability to resist drought.

Co-transplantation of neural stem cells and Schwann cells within poly (L-lactic-co-glycolic acid) scaffolds facilitates axonal regeneration in hemisected rat spinal cord / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells (NSCs) could survive in poly(L-lactic-co-glycolic acid) (PLGA) scaffolds and, when cografted with Schwann cells (SCs), could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function.</p><p><b>METHODS</b>NSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student's t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance (ANOVA) was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials (CMEPs) and Basso, Beattie & Bresnahan locomotor rating scale (BBB) score. The χ(2) test was used to determine the differences in recovery percentage of CMEPs.</p><p><b>RESULTS</b>NSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs ((1.7831 ± 0.0402)% vs. (1.4911 ± 0.0313)%, P < 0.001). Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA + NSCs + SCs group was more than that in PLGA + NSCs group and in PLGA group ((110.25 ± 30.46) vs. (18.25 ± 3.30) and (11.25 ± 5.54), P < 0.01). The percentage of CMEPs recovery in PLGA + NSCs + SCs group was higher than in the other groups (84.8% vs. 50.0% and 37.5%, P < 0.05). The amplitude of CMEPs in PLGA + NSCs + SCs group was higher than in the other groups ((1452.63 ± 331.70) µV vs. (428.84 ± 193.01) µV and (117.33 ± 14.40) µV, P < 0.05). Ipsilateral retransection resulted in disappearance again and functional loss of CMEPs for a few days. But contralateral retransection completely damaged the bilateral motor function.</p><p><b>CONCLUSIONS</b>NSCs can survive in PLGA scaffolds, and SCs promote NSCs to survive and differentiate towards neurons in vivo which even might form synaptic connection. The scaffolds seeded with cells facilitate axonal regeneration and myelination and motor function recovery. But regenerating axons have limited contribution to motor function recovery.</p>

Proteome analysis on interaction between Anoectochilus roxburghii and Mycorrhizal fungus / 中国中药杂志

<p><b>OBJECTIVE</b>To study the mechanism of plant growing promoted by Mycorrhizal fungus through the difference of proteomes.</p><p><b>METHOD</b>The differential proteomes between uninoculated and inoculated endophytic fungi, Epulorhiza sp. on Anoectochilus roxburghii were analyzed by two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrum.</p><p><b>RESULT AND CONCLUSION</b>Twenty-seven protein spots were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Twenty-two candidate proteins were identified by database comparisons. The function of these proteins mostly involved in signal transduction, metabolic regulation, as well as photosynthesis and substance metabolism. The results indicate that the regulator control system of plant is influenced by fungi action, and the positive regulation improves substance metabolism and photosynthesis, which results in strong plant and higher resistance. It is also deduced that silent genes may exist in endosymbiosis plants.</p>

Effect of metoclopramide on capsule endoscopy examination: a randomized study / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of metoclopramide on capsule endoscopy (CE) examination.</p><p><b>METHODS</b>Total 116 patients referred for CE were randomized into two groups with 58 patients in each group. In treatment group patients received 10 mg metoclopramide intramuscular injection after swallowing the capsule and in control group no metoclopramide was administered. The gastric transit time, small bowel transit time, complete endoscopy rate were observed in both groups.</p><p><b>RESULTS</b>The CE examination was completed in 51 patients of treatment group (87.9%) and 48 of control group (84.2%). Mean gastric transit time was (32.45 ± 29.63) min in treatment group and (45.81 ± 40.01)min in control group, there was significant difference between two groups (P<0.05). Mean small bowel transit time was (252.69 ± 113.29) min in treatment group and (258.75 ± 83.83) min in control group, there was no significant difference between two groups (P>0.05).</p><p><b>CONCLUSION</b>Metoclopramide may reduces gastric transit time, but not effect small bowel transit time,which suggests that it might increase the likelihood of complete small-bowel examination in patients undergoing capsule endoscopy.</p>

Cytocompatibility of nano-hydroxyapatite/bacterial cellulose nanocomposites and its residues / 中国组织工程研究

BACKGROUND: The nano-hydroxyapatite/bacterial cellulose (nHAP/BC) nanocomposites has a good prospect of application in bone tissue engineering, and the bone tissue engineered materials and its degradation products Should have excellent compatibility. This study further assessed DAN synthesis cycle using flow cytometry on the basis of evaluating cell compatibility by metabolic 3-(4, 5-dim ethylthiazo 1-2-y 1) -2, 5-Dipheny 1-2H-tetrazolium (MTT) assay. OBJECTIVE: To evaluate the cytocompatibility of a new-pattern nHAP/BC nanocomposites and its residues. METHODS: Effects of nHAP/BC nanocomposites and its residues on morphclogicel changes in osteoblasts were observed using in vitro cell culture method. Effects of nHAP/BC nanocomposites and its residues on osteoblast growth and prclifera'don were evaluated by MTT assay. Cell cycle phase changes were detected using flow cytometry to evaluate matsdal effects on cell proliferation on molecular levels. RESULTS AND CONCLUSION: The nHAP/BC nanocomposites and its residues had neither remarkable effects on cell morphology, nor significant inhibition on osteoblast growth and proliferation. Test of MTT cytotoxicity showed that the average cell proliferation rate was over 80% after treated with the material and its residues, with the cytotoxity grade of 1 (non-toxic). Flow cytometry indicated that the rate of G_0/G_1 was reduced, and the rates of S, G2/M were increased, and the synthesis of DNA was increased, the cellular growth and repair in osteoblasts was accelerated. These indicated that nHAP/BC nanocomposites have good cytocompatibility, and it will be safe and prospected scaffolds in bone tissue engineering.

A new purification methods of small DNAs--the purification methods with silica wool / 生物工程学报

The principal purpose of this study is to set up efficient purification techniques of small DNAs which are suitable for isolation of from tens to three hundred bases of genes. On the bases of the technique, purification methods for big DNA fragments are established. In the experiment, the DNA bands were cut after agarose gel electrophoresis and put into 0.5 mL of tubes with silica wool, glass wood, absorbent cotton and cotton at the bottom. And then 10 000 r/min for 2 min, the liquid was collected. The results indicated that silica wool was the best of the materials. The recovery rate for DNAs below 200bp was over 90%, 85% to approximately 90% for 300bp. And the technique can be applied to purify bigger DNA fragments. The kits for DNA purification hardly recovered DNA below 150bp. The recovery rate for 150bp of DNA was 5%, 60% even for 300bp. The efficiencies of enzymic digestion and enzymic connection for the DNAs purified by the technique were the same as those for the DNAs isolated by the kits. So, the technique is obviously superior to kit purification methods.

Mutations in E154 of Diphtheria Toxin (DT) and Their Biologic Activity / 生物化学与生物物理进展

According to the results of quantum chemistry calculation and the present research status in the relationship between the structures and the functions of DT, the E154 in DT catalyzing domain was mutated to aspartic acid and arginine in order to study the effects of the alteration on the biological activities. By means of gene site-direct mutation, two mutated genes were prepared and the high performance expression was obtained in E.coli system. The results of toxcity studies indicated that the acute toxicity in guinea pig and cytotoxicities of mutant E154D increased slightly in compared with those of recombination wild toxin, and contrarily, those of E154R decreased obviously.

The effects of early escharectomy on resting energy expenditure in the severely burned patients / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effect of early escharectomy on resting energy expenditure (REE) in severely burned patients dynamically with the metabolic monitoring and diagnostic system.</p><p><b>METHODS</b>Fifty-six adult male patients with severe burns were divided into early escharectomy (group A, n = 39, escharectomy within 5 PBDs) and non-early escharectomy (group B, n = 17, escharectomy after 5 PBDs) groups. The wounds of full thickness and deep partial thickness burn in the two groups were all excised and covered with allogeneic skin and autologous micro-skin in the first operation. The changes in REE were observed dynamically at the bedside of the patients with the metabolic monitoring and diagnostic system. The plasma contents of IL-6, IL-8, TNF-alpha and LPS from 9 patients in group A and 7 in group B were also determined dynamically.</p><p><b>RESULTS</b>All patients survived. The REE in both groups was elevated markedly, but REE in group A was lower compared with group B before and after escharectomy within 14 days. (P < 0.05). The plasma level of IL-6, IL-8, TNF-alpha and LPS in group A were obviously lower than those in group B (P < 0.05).</p><p><b>CONCLUSION</b>The hypermetabolic response of burn patients with severe burns could be lowered by early escharectomy, and it seemed to be related to the decrease of the release of proinflammatory mediators.</p>

Acute toxicity of diphenylchlorarsine in mice and rats / 第三军医大学学报

Objective To assess the toxicity risks of diphenylchlorarsine (DA) to environments, human beings and livestock. Methods Totally 120 mice were randomly divided into 6 groups and given DA by gastric gavage at the doses of 32, 30, 28, 26, 24, 22 mg/kg respectively for LD_(50) of DA in mice. The toxicity of DA in rat skin were evaluated by smearing 50 ?l DA at the concentrations of 140, 70, 35, 17.5, and 8.8 mg/ml to an area of 4 cm2, and that of eyes exposure was carried out by dropping 10 ?l DA of 140.7, 70, 7, 0.7 mg/ml in rat eyes. The counterpart skin area and eyes served as control. Results LD_(50) of DA in mice was 28.07 mg/kg, the estimated doses for no-observed-adverse-effect levels (NOELs) were 8.8 mg/ml (0.44 mg) to the skin and 0.7 mg/ml (0.014 mg) to the eyes respectively. Conclusion DA can induce the injuries on the liver, kidneys, esophagus and stomach. High concentration of DA can cause inflammation of the skin and lens opacification, even blind.

Construction of eukaryotic expression vector using neomycin-resistance gene mutant as selectable marker / 生物工程学报

Neomycin-resistance gene is widely used as a selectable marker in eukaryotic expression vector. It codes neomycin phosphotransferase II (NPT II) which confers resistance to various aminoglycoside antibiotic such as G418 and kanamycine. In this work, by site-directed mutagenesis the neo gene mutant was obtained. The expression vector pmDNA using the neo gene mutant as selectable marker has been constructed. After inserting interest luciferase gene, the expression plasmid pmDNAluc + was stably transfected CHO-K1 cells. As a result, the expression positive ratio reaches to approximate 95% and the ratio of high expression colonies is apparently higher than the controls.

Purification of SEB by McAb affinity chromatography and activity analysis / 中国免疫学杂志

Objective:To prepare highly purified Staphylococcal enterotoxin B(SEB) by affinity chromatography and test its activities.Methods:Anti-SEB McAb(1D2) purified by precipitation method with caprylic acid was coupled to Sepharose 4B. And then the SEB was isolated using an affinity chromatography column. In addition, we analyzed the superantigen activity and antigen activity of SEB.Results:The purification efficiency of SEB was 60.71% by affinity chromatography. Its purity was higher than those of standard preparation and the SEB purified by ion change chromatography. At the same time, the purified SEB by affinity chromatography possesses favourable activities of superantigen and antigen.Conclusion:McAb affinity chromatography could be used for purification of SEB with high efficiency.