The intraspecies quorum sensing system of Streptococcus mutans is involved with com genes family.ComE is a kind of response regulator and act as a promoter to the quorum sensing genes.S.mutans comE mutant strain IFD140?comE was constructed using the inframe-deletion system via twice homologous recombination.In current genetic studies of S.mutans,insertion duplication and allelic exchange mutagenesis techniques routinely create polar effects to downstream genes.In-frame deletions are essentially free of these polar effects because the mutation does not introduce any genetic markers.By PCR,sequencing and RT-PCR,it was confirmed that IFD140?comE has only 717bp deleted within the comE gene and the transcription of the downstream gene comD was not interfered.The research of the morphological characteristics indicated that IFD140?comE formed clumps and cells accumulated at the bottom of the glass tubes and light-microscopic observations displayed that the mutant strain formed significantly longer chains compared to those formed by the wild strain.The successfully construction of IFD140?comE lay a foundation for further quorum sensing research.

It has been found by Ju('81)that HRP could be anterogradely transported forlong distances.Based on this fact the rate of anterograde transport was investigatedin the present study,and,at the same time,the rate of retrograde transport and thetime of disappearance of HRP from the labeled sites were observed.Twenty tworabbits,weighing 2～2.2 kg,were used.The HRP was injected into the lower lumbarspinal cord unilaterally.The animals were sacrificed after 12 hours to 7 days andwere processed with benzidine and o-dianisidine.The anterogade labeling in the dorsalaccessory olivary nucleus and the retrograde labeling in the red nucleus and thenucleus raphe pallidus were chosen for study.It was quite unexpected to find that the anterograde and retrograde labelingsparalled each other in time as well as in intensity.They appeared at the same timeand waxed and waned practically in full accord.Labeling of the brainstem firstappeared at 18 hour's survival,reached its peak at the 2nd day,and then graduallyfaded away till at the 7th day when only traces of labeling remained.In the casewhich showed the earliest labeling the distance between the injection site and theobex,which was at about the same level as the most densely labeled parts of thedorsal accessory olivary nucleus and nucleus raphe pallidus,was measured to be 265mm and the rate of transport,the same for anterograde and retrograde transports,was calculated to be more than 350mm per day.Counting from the time of theearliest labeling,HRP was found to remain at the labeled site for as long as 5～6 days.The period of net accumulation of HRP at the labeled sites was about 1 day.Thus,the best survival period would be roughly the time required for HRP to travel thefiber tract plus 1 day.Neurons of the red nucleus and the nucleus raphe pallidus differ greatly intheir morphology,physiology as well as biochemistry.The results in them however,were similar.This,in connection with observations on other nuclei,both anterogr-adely and retrogradely labeled,suggests that the rate of transport and the duration ofpreservation of HRP in the central nervous system are basically the same in differentneuronal systems.

Objective To study the condensation mechanism of aminoglucomannan(AGM)with plasmid DNA and some influencing factors in this process.Methods The polysaccharide-DNA complex was analyzed with agarose gel electrophoresis by observing the changes of DNA bands under various influencing conditions including different pH,ionic strength(NaCl concentration),temperature and plasmid DNA sorts.Results The new bands appeared in the slow migration positions after reaction between AGM and plasmid DNA,and the changes of DNA bands content were dependent on AGM concentrations.The condensation degree could be effected by pH,temperature,and ionic strength.Conclusion Our study suggests that the AGM can be condensed with plasmid DNA in proper conditions.

Objective:To discuss treatment of complete response cases after neoadjuvant radiotherapy in rectal cancer. Methods:This retrospective study analyzed clinical data of 84 rectal cancer cases with pre-operative neoadjuvant chemoradiotherapy in our hospital from January 2010 to Augnst 2014. Results:After neoadjuvant chemoradiotherapy, 33 patients presented clinically complete response at a rate of 39.3%. After post-operative pathologic examination, among clinically complete response cases, six cases exhibited patho-logically complete responses at a rate of 18.2%. No recurrence or disease progression occurred within 12-36 months of post-operative follow up. Conclusion:Neoadjuvant chemoradiotherapy can significantly lower tumor stage and promote clinically complete remission of some patients. However, for clinically complete remission cases, further radical surgery should be provided.

[Objective] To investigate the effects of the bioactive constituents of green tea polyphenols epigallocatechin gallate (EGCG) on low density lipoprotein receptor (LDLR) function of HepG2 cells.[Methods] The optimal concentration and cell proliferation of HepG2 cells were determined by CCK8 assay,and Western blotting was used to determine LDLR and PCSK9 protein levels,respectively,and LDL uptake in HepG2 cells was detected by fluorescence microscope.[Results] EGCG elevated LDLR protein expression,reduced PCSK9 protein expression and promoted LDL uptake in HepG2 cells.[Conclusion] EGCG may increase LDLR abundance by down-regulating PCSK9 protein and attenuating LDLR protein degradation,which providing a new approach for lipid lowering therapy.

BACKGROUND: Most animal experiments of transgene are derived from mice; therefore, it is necessary to establish a focal cerebral ischemiareperfusion model and significant to prevent and cure ischemic cerebrovascular diseases.OBJECTIVE: To establish a convenient and reliable model with middle cerebral artery occlusion reperfusion (MCAO/R) in mice.DESIGN: Randomized controlled animal study.SETTING: Institute of Cerebrovascular disease, Affiliated Hospital of Medical College of Qingdao University.MATERIALS: Twenty healthy BALB/c mice, of both genders, weighing 25-30 g, of SPF grade, were divided into sham operation group (n=5), ischemia group (n=10) and 22-hour reperfusion group (n=5) on the basis of digital table. In addition, according to digital table, 130 healthy male Kunming mice were divided into sham operation group (n=10), 24-hour ischemia group (n=30), 2-hour ischemia/22-hour, 46-hour and 70-hour reperfusion groups with 30 in each group; meanwhile, 30 female mice were divided into sham operation group, 24-hour ischemia group and 2-hour ischemia/22-hour reperfusion group with 10 in each group. All Kunming mice were weighing 25-30 g and of SPF grade.METHODS: The experiment was carried out in the Institute of Cerebrovascular Disease, Affiliated Hospital of Medical College of Qingdao University from July 2005 to March 2006. The 6-0 suture with silica gel covered at an end was sent from the left external carotid artery (ECA) into internal carotid artery (ICA) till arriving at the initiation of middle cerebral artery (MCA) to block the blood stream in it, then drawing the suture from ICA 2 hours after occlusion to accomplish reperfusion. Mice were cut off their heads in sham operation group at 24 hours after operation, in ischemia group at 24 hours after blocking blood stream and in reperfusion group at 24, 48 and 72 hours after operation. Reliability of models was evaluated with neurology score and tetrazolium chloride stain. Longa standard scores: neurology score ≥ 1 point was regarded as successful models;coronal sections of brain tissue were stained with tetrazolium chloride, and the white region was regarded as infarcted volume.MAIN OUTCOME MEASURES: Neurology score and infarcted volume after staining of triphenyltetrazolium chloride in brain tissue.RESULTS: All mice were involved in the final analysis. ① Successful rate was 20% of BALB/c mice, 66.7%-73.3% of male Kunming mice and 40%-50% of female Kunming mice. ② Brain sections of BALB/c mice in sham operation group were orange at both sides of cortex and infarction focus was not observed. A big infarcted volume was observed on brain sections of mice in ischemia group, and infarcted volume counted for 50%-70% as homonymy hemisphere on optochiasmatic coronal sections. The condition of Kunming mice was similar to that of BALB/c mice, but infarcted volume counted for 40%-65%. In addition, condition in ischemiareperfusion group was similar to that in ischemia group. A big infarcted volume was observed on brain sections, and infarcted volume counted for 50%-75% as homonymy hemisphere on optochiasmatic coronal sections.The condition of Kunming mice was similar to that of BALB/c mice, but infarcted volume counted for 40%-65%.CONCLUSION: The model with MCAO/R in mice characterizes by relatively smaller trauma, and the ischemic region is stable; therefore, it can be used to accurate timing control of ischemia/reperfusion. This model is an ideal one for researching pathophysiological changes, prognosis and therapy in cerebrovascular disease.

Objective To evaluate the value of ultrasound in diagnosing ductal carcinoma in situ (DCIS). Methods The sonographic characteristics of 12 DCIS which were confirmed by pathology were analyzed retrospectively. Results The ultrasound image of DCIS could be divided into four types;the solid mass nodule, mammary dysplasia, mix mass nodule, the dilated duct type. Micro calcification had high incidence rate. Ultrasonic diagnosis accordance rate was 50.0 %. On molybdenum target mammograms, the tumor appeared as a cluster of calcified spots in 8 cases, and the accuracy rate of diagnosis of was 66.7 %.Conclusion There are no typical characters of DCIS in ultrasound image. However, some characteristics are suggestive and can help to differentiate them from the benign tumors, such as small nodule, irregular shape,obscure boundary, and microcalcification. When sonography combine with molybdenum target mammography,the accuracy rate of diagnosis will be improved.

?AIM:To study the clinical value of non-steroidal anti-inflammatory drug in adjuvant treatment of intravitreal triamcinolone acetonide ( IVTA ) for macular edema caused by retinal vein occlusion ( RVO) .?METHODS: Forty - eight eyes in 48 patients were randomly divided into trial and control group ( 24 eyes each ) in this prospective study. In the trial group, additional pranoprofen drops was administered from 1d before IVTA to 30d after injection. Central foveal thickness ( CFT ) was measured with optical coherence tomography ( OCT ) . Available documents of best corrected visual acuity ( BCVA ) , CFT, intraocular pressure and complications pre- and post-injection at 3d, 1,2wk, 1 and 3mo were evaluated.?RESULTS: After IVTA, BCVA was improved in both groups at different levels; but there was no statistically significant between two groups at each time point ( P>0. 05). The CFT values were 629 ± 43μm vs 605 ± 57μm before IVTA in the trail vs control groups (P>0. 05). The values were 432±74μm vs 511±32μm (t=7. 533, P<0. 05), and 275±54μm vs 379±29μm (t=13. 212, P<0. 05) of the trial vs control groups at 1 and 3mo after IVTA, respectively. Ocular hypertension occurred in 5 eyes after injection in trail group, and was controlled with anti-glaucoma medication and one eye with filtration surgery. Progression of cataract was noted in 3 of 35 phakic eyes and cataract surgery was performed in 2 eyes at 4-12mo after injection in trail group. Progression of cataract was noted in 4 eyes and cataract surgery was performed in 2 eyes at 4- 12mo after injection in control group. No retinal detachment and endophthalmitis happened during the whole period of follow-up.?CONCLUSION: Application of non - steroidal anti -inflammatory eye drops in perioperative period can be useful to improve the outcome of IVTA for macular edema, which needs further evaluation.

Objective: To clone the 5＇-flanking region of the human CD34 gene containing transcriptional regulatory sequence (TRS). Methods: According to the registered 5＇-flanking region of CD34 gene, two pairs of primers were designed and net-PCR was used to amplify 661 bp long TRS of CD34 gene. The CD34 TRS fragment was cloned into reported plasmid pEGFP-1. The role of the regulating the specific expression of recombinant plasmid pCD34 EGFP in hematopoietic and non-hematopoietic cells was observed. Results: Restrictive endonuclease identification and DNA sequencing provedthat the CD34 promoter cloned was consistent with the sequence reported to a large extent. It could induce the EGFP gene to express in hematopoietic cell line K562 specifically, while has no effect on hepatocellular carcinoma cell HepG-2. Conclusion: The cloned CD34 gene TRS has the effect of regulating gene expression specifically. The study established the fundament for the construction of specific gene expression vector used in hematopoietic system cells.

The effect of reaction media cosolvent water activity, temperature and pH on Novozym 435-caulyzed enantioselective esterification of ketoprofen was systematically explored. Novozym 435 showed high catalytic activity and enantioselectivity in cyclohexane; E value increases markedly by addition of toluene to cyclohexane; the optimum temperature and the initial water activity were found to be 30℃ and 0.09 respectively; pH shows little effect on enzymatic reaction wilson the scope studied.