| Secondary pancreatic infection(SPI), which usually occurs 2~3 weeks later after the onset of SAP, is the main cause of death in patients with severe acute pancreatitis(SAP). The essence of SPI is entergenous infection which is caused by the translocation of bacteria and endotoxin from the digestive tract. Hence, Whether the entergenous infection is controlled or not maybe have direct impact on the prognosis of SAP patients. Actually, the occurrence, progress and prognosis of many kinds of diseases are related to the entergenous infection. But being different from the others, drainage of the peripancreatic infection after the occurrence of SPI is very difficult, which needs many times of operation. Especially, the infection can be a vicious cycle, in which the systemic septicemia can be caused by localized infection or vice versa. It is difficult to decrease the mortality and improve the quality of life by surgical drainage, prophylactic antibiotics, selective digestive decontamination (SDD), enteral nutrition and mucosal protective agents. Although broad-spectrum antibiotics are effective in controlling the systemic septicemia, and so does SDD in decreasing bacteria and endotoxin. They both caused the over-multiplication and dominant settling of drug-resistance bacteria. If these kinds of bacteria translocate to the peripancreatic necrotic tissue, the concentration of antibiotics which pass through the blood-pancreatic barrier is not intense enough to kill them. Moreover, the more operations patients have, the more painful they are, and more payment they have. In a word, the quality of patient's life is decreased significantly. Hence, a new strategy of treatment and prophylactics is needed to make up the in sufficiency of the above-mentioned therapeutic methods.As an innate immunological agent, human defensin 5(HD-5) is promising because of its broad-spectrum microbicidal activity and resistance to digestive enzymes. In the present study, we hope that the recombinant HD-5 can be obtained by gene recombination techniques ex vivo and used in the treatment and prophylactics of SPI in the future.In order to understand SPFs characteristics, 60 cases of SAP patients from 1980 to 1999 were reviewed. The main results were shown as follows: (1) There was no significant difference on age and gender between SPI group (n=29) and non-SPI (NSPI) group(n=31). (2) The average days in hospital, payment, days of fever, out-patient days, days of high WBC count were significantly higher in SPI patients than that in NSPI patients. In addition, The interval from onset of SAP to stool was longer than that in NSPI patients. While five of seven patients without stool in SPI group was dead, and only one patient without stool died in NSPI group. The fatality rate (6 in 11) of infective pancreatic necrosis is the highest, and that (1 in 17) in pancreatic abscess were the second, while there was one patient with pancreatic pseudocyst combined infection. There was no significant difference in the scores of Ranson and high risk factors of China Medical Association between the two groups except the APACHE II scores. The main pathogenic bacteria were Enterobacteriaecae and Psudomonas. Mixed infection is the main type. All of these results show that the essence of SPI is entergenous infection, and SPI affected the prognosis of SAP patients. The present therapeutic methods are hard to prevent the onset of entergenous infections. It is necessary to find a new strategy.According to the findings above and the research of HD-5, four experiments were designed to investigate the possibility of obtaining the recombinant human defensin 5(rHD-5) by constructing the recombinant plasmid, transfecting CHO-K1 cell line. Meanwhile, the antibacterial and bactericidal activity of rHD-5 peptide was also detected. In the first experiment, we found thatthere exist HD-5 mRNA transcription in ileal mucosa, that no discrepancy was found in 500bp products by RT-PCR as comparing with the HD-5 sequence from Genebank, that the gene of interest (HD-5 cDNA) o...
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