ABSTRACT
Hydrogel nanoparticles (NPs) were synthesized by precipitation polymerization method with N-isopropyl acrylamide (NIPAm), acrylic acid (Aac), N-tert butyl acrylamide (tBAM) and N,N'-methylene bisacrylamide(Bis) as thermosensitive monomer,negative monomer,hydrophobic monomer and crosslinker, respectively. The morphology of the resulting NPs was characterized by scanning electron microscopy(SEM),and the size and the particle size distribution were investigated by dynamic light scattering (DLS). The dynamics test was also carried out to investigate adsorption property of NPs. The results showed that NPs was spherical with uniform particle size and narrow distribution. NPs had the best adsorption performance to lysozyme when the monomer molar ratio was optimized to Aac 20%,tBAM 40%,NIPAm 38% and Bis 2%. Meanwhile, when the particle size of NPs decreased from 386. 20 nm to 77. 25 nm, the adsorption capacity increased gradually. The adsorption rate could reach up to 67.8% within 5 minutes. The thermosensitive of NPs provided a new candidate for the adsorption and separation of lysozyme with good reusability.
ABSTRACT
<p><b>OBJECTIVE</b>To study the clinical application value of middle segment pancreatectomy in the treatment of benign tumors of the amphi-neck of the pancreas.</p><p><b>METHODS</b>Fifteen cases were retrospectively analyzed treated from November 2005 to June 2009. There were 3 male and 12 female aging from 30 to 50 years. They all received middle segment pancreatectomy for benign tumors of the amphi-neck of the pancreas.</p><p><b>RESULTS</b>There was no death during perioperative period. All the 15 patients received middle segment pancreatectomy. Fourteen of them received the closure of broken ends of pancreatic head, pancreaticojejunostomy (mono-anastomosis) and the rest one received dipl-anastomosis. Postoperative pathology showed that in the 15 patients, 1 got solid-pseudopapillary tumor of the pancreas, 3 got non-functional islet cell tumor, 11 got cystadenoma of pancreas. Three of them got pancreatic fistula and were self cured in 3 months. Follow-up visits to all the patients kept in the following 2 to 45 months. There was no death. No patients got new-onset diabetes and pancreatic pseudocyst. And their tumors were not relapsed.</p><p><b>CONCLUSIONS</b>There is an exact therapeutic effect of middle segment pancreatectomy for benign tumors of the amphi-neck of the pancreas. The treatment has little function damage to patients' endocrine and external secretion. The incidence rate of pancreatic fistula in middle segment pancreatectomy is higher than that in pancreaticoduodenectomy. As long as the drainage is kept unobstructed, most of the pancreatic fistula can be self cured.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Follow-Up Studies , Pancreatectomy , Methods , Pancreatic Neoplasms , General Surgery , Retrospective StudiesABSTRACT
<p><b>OBJECTIVE</b>To study the selective effect to tumor cells mediated by a recombinant adenoviral vector carrying E2F-1 promoter.</p><p><b>METHODS</b>The AdEasy-1 adenoviral vector system was used in this experiment. Several recombinant adenovirus with tumor-targeting E2F-1 promoter were constructed and then the E2F-1 promoter gene was checked by PCR and sequencing. The two adenovirus expressing GFP gene which is regulated by E2F-1 promoter or CMV promoter were used to respectively transfect tumor cells and non-proliferating normal cells, then observed and analyzed the different results caused by different promoters. Vpr gene was cloned into the targeting recombinant adenovirus. The new adenovirus named rvAdE2F-1/vpr was used to transfect tumor cells SMMC-7721, LS174T and non-proliferating normal cells H292, L-02. The surviving rate of each group was registered; the level of E2F-1 protein expressed in normal and tumor cell lines were checked by Western Blot.</p><p><b>RESULT</b>E2F-1 promoter can regulate the downstream gene GFP selectively expressed in LS174T and its activity in LS174T was similar with CMV promoter's; Vpr gene regulated by E2F-1 promoter can suppress the proliferation of tumor cells and no toxicity to normal cells; In all of the tumor cells, a much higher level of E2F-1 was expressed compared with normal cell lines. E2F-1 promoter's activity correlated well with E2F-1 protein levels.</p><p><b>CONCLUSIONS</b>E2F-1 promoter can control a selective cell killing to cancer cells, with no effect to normal cells. The system of E2F-1 promoter is a useful method for tumor-targeting gene therapy.</p>