Construction of CTLA-4-Ig fusion gene in pBudCE4.1 expression vector

CTLA-4 inhibitory signals prevent cell cycle progression and IL-2 production, leading to a halt on an ongoing immune response. CTLA4-Ig fusion proteins con-tain the extracellular domain of CTLA-4 and Fc fragment of human IgG antibody. In this study we aimed to fuse the ctla-4 gene encoding the extracellular domain of CTLA-4 molecule with igg1 gene encoding Fc region of human IgG. After primer design, PCR reaction was performed using pfu polymerase en-zyme and specific primers. PCR amplified fragment was ligated into the vector con-taining the human igg1 gene. The resulting fusion fragment of ctla-4 and human igg1 genes was ligated to pBudCE4.1 expression vector. Extracellular domain of ctla-4 gene was ligated to igg1 gene and then ctla4-ig fragment was cloned into pBudCE4.1 vector. Construction of the expression vector was confirmed by restriction pattern analysis and sequencing. By confirming the construct, in the next step, the recombinant DNA will be used to produce CTLA4-Ig recombinant protein for the clinical uses

Effect of calcium hydroxide and chlorhexidine medicaments on the apical seal

Leakage of the root canal system is an importent consideration when placing an intracanal medicament. The aim of this in vitro study was to compare the effect of calcium hydroxide and 1% chlorhexidine gel as intracanal medicaments on tooth apical seal. Seventy extracted, single-rooted maxillary anterior teeth were divided into the three experimental groups [n=20]. All root canals were instrumented with step-back technique and divided into three groups. Group 1 had root canal dressing with calcium hydroxide; group 2 had root canal dressing with 1% chlorhexidine gel and group 3, did not receive a dressing. The roots were incubated in 100% humidity at 37°C for 7 days. After removing the dressings, all canals of the experimental groups were obturated using a cold lateral condensation technique. The root surfaces of all specimens were coated with two layers of nail varnish, except for the 2 mm surrounding the apical foramen. Apical sealing ability was assessed by dye leakage method and the specimens were examined under a stereo-microscope. Dye penetrations were measured and analyzed using ANOVA and post-hoc Tukey test. Calcium hydroxide group had the least frequency of apical leakage at 2 mm level [0.46 +/- 0.40 mm], whilst chlorhexidine group showed the greatest apical leakage [0.86 +/- 0.42 mm]. There was statistical difference between group 1 and 2 [P<0.05], but no statistical difference between group 1 and 3, or between groups 2 and 3 [P>0.05]. Intracanal calcium hydroxide medicament may decrease apical leakage of gutta-percha root fillings when AH26 sealer is used; chlorhexidine may increase the leakage