The dose-response relationship between low-dose ionizing radiation and thyroid hormone of medical workers / 中国辐射卫生

Objectives To explore the dose-response relationship between low-dose ionizing radiation and thyroid hormone levels of radiation medical workers and provide theoretical basis for occupational health protection to this population. Methods Using a prospective cohort study design, we collected health examination reports on employees that worked on jobs with occupational exposure to radiation at hospital with individually dose monitoring data for 1 237 workers. The effective cumulative radiation dose was divided into three groups: 0～2.586 mSv, 2.586～3.757 mSv, 3.758～31.272 mSv by the interquartile range. The low-dose group was used as a reference to compare the changes in thyroid hormones of medical workers in different cumulative radiation dose groups. The generalized linear models and restricted cubic spline model were used to examine the association and dose-response relationship between the cumulative effective dose and changing thyroid hormones. Results There were statistically significant differences in changing thyroxine (T4) and Free triiodothyronine (FT3) levels among three different dose groups of 1237 subjects (P < 0.05). The results of generalized linear models analysis revealed that 2.586～3.757 mSv was a significant risk factors of changing T4, with β of 3.514 (95% confidence interval [95% CI]: 0.900～6.128) after adjusting for gender, age, working duration, occupation, medical level and smoking, while the association with changing FT3 was not observed (P > 0.05). The restrictive cubic spline (RCS) model analysis indicated a non-linear dose-response correlation between cumulative radiation dose with changing T4 (P = 0.023). Conclusion Long-term exposure to low-dose ionizing radiation could induce the thyroid damage among medical occupational population. And there is a dose-response relationship between cumulative radiation dose and changing thyroxine.

Simultaneous determination of 14 chlorinated hydrocarbons in urine by headspace gas chromatography-mass spectrometry / 中国职业医学

OBJECTIVE: To establish a headspace gas chromatography-mass spectrometry method for the determination of 14 chlorinated hydrocarbons in urine. METHODS: The urine sample 4.00 mL and anhydrous sodium sulfate 3.00 g were added into a 10.00 mL headspace bottle, then the headspace bottle was maintained at 70 ℃ for 40.0 min. After headspace pretreatment, 14 chlorinated hydrocarbons in headspace air were separated in the DB-5 MS capillary column of the gas chromatography and detected by mass spectrometer. RESULTS: There was a good linear relationship of 14 chlorinated hydrocarbons in urine in the range of 0.62-1 630.00 μg/L. The linear correlation coefficient was greater than 0.999 0.The minimum detectable concentration was 0.19-0.43 μg/L and the minimum quantitative concentration was 0.62-1.44 μg/L. The average recovery rate was 89.8%-107.1%. The within-run relative standard deviation(RSD) was 4.0%-8.5% and the between-run RSD was 6.3%-9.1%. Urine samples can be stored at 4 ℃ or-8 ℃ for 3 days and below-20 ℃ for 7 days. CONCLUSION: This method is rapid, simple, sensitive, accurate and has little interference,which can be used as a method for detecting 14 kinds of chlorinated hydrocarbons in urine samples of patients with occupational poisoning.

A calcified biomimetic scaffold for bone tissue engineering in the treatment of martialarts-induced ankle injury / 中国组织工程研究

BACKGROUND:In sports or in daily life, damage due to sudden power, especialy due to non-physiological release,is commonly seen. For example, during basketbal, soccer, rugby, or martial arts movement, oppositional and explosive movements result in a higher incidence of ankle injuries. While conventional methods can improvesymptoms, the long-term efficacy is unsatisfactory, accompanied by a higher incidence of complications that are likely to cause secondary damage. OBJECTIVE:To prepare a calcified biomimetic scaffold for bone tissue engineering and to observe the therapeutic effect of this scaffold onmartialarts-induced ankle injuries. METHODS:Eighty patients withmartialarts-induced ankle injury were selected from Chengdu Sport Institute between December 2014 and December 2015. These patients were randomly assigned to control group with drug treatment and biomimetic scaffold group with calcified biomimetic scaffold implantation (n=40 per group). Acelular suspension prepared by goat cartilage was used to make cartilage tissue blocks with a calcified layer with a diameter of 8 mm in a prechiled abrasive apparatus. Then, the calcified biomimetic scaffold for bone tissue engineering was prepared using lyophilization and chemical crosslinking methods. RESULTS AND CONCLUSION:Osteochondral tissues were partialy hyalinized on the surface with the presence of osteochondral calcified layer. The hyalinized cartilage was white in color, the calcified layer existed between normal osteochondral tissues, and the subchondral bone was considered as the cancelous bone. Then the calcified layer was stained using hematoxylin-eosin. We found that cartilage cels in the calcified layer were basicaly removed, forming “empty nests” one by one. But the structure of bone cartilage in the tissue block, the calcified layer and the subchondral bone retained wel. For pain assessment, visual analog scale scores were detected and showed no difference between two groups prior to treatment (P> 0.05), but became significantly higher in the biomimetic scaffold than the control group at 1 and 4 weeks after treatment (P< 0.05). Besides, the biomimetic scaffold exhibited better therapeutic efficacy than the drug treatment (P< 0.05). Overal, this study successfuly prepare the calcified biomimetic scaffold for bone tissue engineering that is suitablefor repair of sport-induced ankle injuries.

Discovery of topAp4 as a new sensing element for TNT detection / 军事医学

Objective To screen the sensing elements for TNT detection in Escherichia coli genome.Methods A genome promoter library with cutting E.coli K-12 MG1655 genome was constructed.Bacterial luciferase luxCDABE was used as a reporter gene during promoter screening.We discovered TNT sensing elements through several rounds of screen-ing.Through analysis of sensitivity, specificity and timeliness, the promoter activity of the elements was evaluated,and the functional sequence of the elements was further confirmed.Results and Conclusion We successfully constructed an E.co-li K-12 MG1655 genome library , from which a TNT sensing element was discovered,which had a good performance in the analysis of sensitivity, specificity and timeliness.In this study, we reported that the topAp4 is a TNT sensing element for the first time.We also verified its excellent promoter activity.

Inhibitory effect of metformin on proliferation of megakaryocytic leukemia cell line Dami and its mechanism / 吉林大学学报(医学版)

Objective To study the effect of metformin on the growth of megakaryocytic leukemia cell line Dami and to explore the molecular mechanisms of the inhibitory effect of metformin on the proliferation of Dami. Methods The Dami cells were cultured and divided into control and 1,2,4,8,16 and 32 mmol·L-1 metformin groups.Then MTT test was performed to detect the inhitory rate of proliferation of Dami cells after treated with different concentrations of metformin. Flow cytometry was used to examine the distribution of cell cycle, and Western blotting was carried out to analyze the expressions of Cdc2 and CylinB1 and the phosphorylation of Cdc2. Results The MTT results showed that compared with control group,the inhibitory rates of proliferation of the Dami cells in 32 mmol·L-1 metformin groups at 0,24,48,72 and 96 h (35.1%±2.3%,49.7%±5.1%, 78.85±0.9%,79.1%± 3.0%%,and 85.2%± 3.2%)were significantly increased(P<0.01),Furthermore, after metformin treatment for 72 h,the inhibitory rates of proliferation of the Dami cells in 1,2,4,8,16 and 32 mmol·L-1 metformin groups were (33.8 ± 0.3)%,(51.9 ± 0.2)%,(59.4 ± 1.6)%,(65.5 ± 2.0)%, (75.5±0.9)%,and (79.1±3.0)%,respectively. Metformin inhibited the growth of Dami cells in a time-and dose-dependent manner. The flow cytometry results results revealed that compared with control group, the percentages of Dami cells in G2/M phase in 1,2 and 4 mmol·L-1 metformin groups were increased from (26.0± 0.5)% to (38.5 ± 1.5 )%, (48.4 ± 1.1 )%, and (58.2 ± 2.7 )%;there was significant difference in the percentages of Dami cells in G2/M phase between control group and 4 mmol·L-1 metformin group (P<0.01). Western blotting analysis showed that compared with control group, the expressions of Cdc2 and CyclinB were evidently reduced, the phosophorylation of Cdc2 at Tyr1 5 was up-regulated, and the phosphorylation at Thr1 6 1 was down-regulated.Conclusion Metformin can inhibit the growth of Dami cells and induce G2/M arrest,and its mechanism may be related to inhibiting the activation of Cdc2/CyclinB1 complex.

A high-fidelity DNA unidirection synthesis method:preliminary exploration / 军事医学

Objective To establish a simple but quick method to improve the high fidelity of the synthesis of DNA frag -ments.Methods High fidelity DNA unidirection synthesis method (HFUS) was presented and used that involved Phusion DNA polymerase, BsrDⅠrestriction enzymes and λexonuclease.Using the same system at different temperatures , HFUS method synthesized one positive single-strand DNA and several reverse single -stranded DNA one by one into the target DNA fragment.Results Two random sequences DNA fragments of 340 bp and 450 bp were synthesized using HFUS meth-od.Conclusion This article explores a new method for the synthesis of genes .Through the harvest of 450 bp DNA, HFUS may promise to be a new approach to the synthesis of DNA .

Animal cell screening system based on GS efficient expression vector and its application / 军事医学

Objective To obtain highly expressing cell lines by inserting the glutamine synthetase (GS) screening system and replacing the promoter of the vector.Methods The mutation of the point BamHⅠwas induced to build a new vector pIRES2-EGFP.The marker gene GS was inserted by AseⅠ and NheⅠ, and the promoter hCMV was replaced by PacⅠand NheⅠ.The new vector pHGS1.0 and the vector pIRES2-enhanced screen fluorescein protein( EGFP)-B were inserted by the recombinant protein TEM8 ( 1-227 )-VEGFR1 domain2-IgG2 ( TV-IgG2 ) gene to analyze the advantages of the expression.Results The glutamine synsthetase is successfully inserted, the human cytomegalovirus replaced, and recombinant protein is increased 5-fold by human immunoglobulin quantification kit.Conclusion The GS system is a highly protein expressing system.

Mutation analysis of STK11 gene coding region for 20 Chinese patients with Peutz-Jeghers syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the sequence of STK11 gene coding region in 20 patients with Peutz-Jeghers syndrome and identify the point mutations in STK11 gene associated with the occurrence of the disease.</p><p><b>METHODS</b>Blood samples were collected from 20 inpatients with Peutz-Jeghers syndrome treated in our center between January 2009 and October 2010. The sequence of STK11 gene coding region was analyzed using PCR and DNA sequencing and compared with the normal sequence of STK11 gene.</p><p><b>RESULTS</b>Of the 20 patients with Peutz-Jeghers syndrome, 14 showed STK11 gene mutations in the coding region, including 1 patient having two mutations and 13 patients with a single mutation site. In one case, sequence analysis of the STK11 gene identified a novel type of STK11 germline mutation, in which the cytosine (C)460 was substituted by guanine (G) in exon 3 to result in a new amino acid at codon 154. Four patients from 2 families were found to have a common mutation. The remaining 6 patients were not found to have mutations in STK11 gene coding region.</p><p><b>CONCLUSION</b>Mutations of STK11 gene is a major cause of Peutz-Jeghers syndrome. The missense mutation of 460 C→G in exon 3 of STK11 gene is a novel mutation associated with Peutz-Jeghers syndrome.</p>

Design of livin antisense oligonucleotides with computer / 中国临床药理学与治疗学

AIM: Antisense oligonucleotides against livin were designed with computer software. METHODS: Antisense oligonucleotides were designed according to the secondary structure of livin mRNA which was simulated with RNAdraw and Sfold. And then these oligonucleotides were transfected into Hela cells for inducing apoptosis. RESULTS: Five antisense oligonucleotides were designed using RNAdraw and Sfold, and effectively induced Hela cell apoptosis. CONCLUSION: The approach is effective and feasible to design antisense oligonucleotides by means of calculation with two kinds of software.

Livin——Potential target for cancer treatment / 中国药理学通报

Livin is a novel member of IAPs (inhibitors of apoptosis protein) family, which is expressed highly in a variety of tumors but not in majority of normal tissues. This protein contains a BIR domain and a RING finger domain just like other members of IAPs. It will be of great sigificance to investigate the relationship between Livin and tumors, and it might be a potential target for anti-cancer drugs.

Screening for inhibitor of vascular endothelial growth factor from random peptide library / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To screen for the inhibitor of vascular endothelial growth factor (VEGF) 165 from random peptide library.</p><p><b>METHODS</b>Positive phage clones were rescued after two rounds of panning and competitive elution. Its affinity activity to KDR was monitored through ELISA, immunohistochemical method, Chicken CAM assay and MTT.</p><p><b>RESULTS</b>Five specific binding positive target molecule phage clones were obtained which were able to bind to cells whose surface had high KDR, among which, clone 3 and 13 could effectively block the vascularization of the chorioallantoic membrane of chick embryo, but they were not inhibitive on the proliferation of high KDR expression cells.</p><p><b>CONCLUSION</b>The peptides, being the inhibitors of VEGF, may be useful in the treatment of cancers.</p>

Identification of the antigenic determinants of human augmenter of liver regeneration (hALR) recognized by its monoclonal antibodies / 中国免疫学杂志

Objective:Identification of the antigenic determinants of hALR.Methods:Theoretic antigenic determinants of hALR was predicted by using Hopp&Wodds method and and Goldkey software package.The four polypeptides according to the amino acid sequences of the predictive linear epitopes of hALR were synthesized and were used to analyze the antigenic determinants of hALR recognized by antibodies.Results:The polypeptides corresponding to residues 6～5,68～80 and 105～112 of hALR were its antigenic determinants.Conclusion:Prediction of the protein antigenic determinants by computer program and detection of them by competitive ELISA with synthesized polypeptides is a useful method of identification of the antigenic determinants.

Isolation of Peptides Binding to KDR Specifically Using Phage Display / 中国肿瘤生物治疗杂志

Objective: To isolate small molecular polypeptides which bind to KDR specifically using C7 and 12 peptide libraries. Methods: KDR/IgGFc was coated directly on plates, C7 and 12 peptide libraries are then applied, followed by vigorous washings in washing buffers to remove most non-specifically bound phage and to select specific phage particals by VEGF suspension and elution in acid buffers. The positive phage clones were detected by ELISA, cell-ELISA and competitive binding ELISA. Results: After three washes, 12 positive phage clones were selected and sequenced. Conclusion: A conserved peptide motif was not found in these sequences. The peptide binding to KDR specifically may be helpful for lead drug to improve selectivity and decrease the side effect of anti cancer drug in clinical treatment.

Seting up an ABC-ELISA method for assaying Neuron-Specific Enolase and it's application research / 中国免疫学杂志

The authors developed an ABC-ELISA method using the double antibody sandwich.The sandwich is composed of labled and unlabled rabbit antihuman Neuron- Specific Enolase.The method is sensitive, specific and it's standard curve is linear interrelated. In clinical practice,it can be used to assay the concertration of NSE in serum and diagnose small cell cancer of the lung.