Objective To discuss the relationship of congenital choledochus cyst(CCC)with occurrence of pancreatitis in adults and methods of surgical treatment.Methods The clinical data of 17 adult patients with congenital choledochus cyst who underwent surgical treatment from 1997-2005 were analyzed retrospectively.Results Clinical diagnosis was made mainly by B-ultrasound,MRCP,intraoperative cholangiography,ERCP and CT scans.Among 17 cases,10 cases were congenital choledochus cyst typeⅠ,4 cases type Ⅱ,1 case type Ⅲ,1 case type Ⅳ and 1 case type Ⅴ;and associated with cholelithiasis in 14 cases(bile pigment stone in 11cases,cholesterol calculus 3cases),chronic cholecytitis 5 cases,polypoid lesions of gallbladder 1 case,anomalous pancreaticobiliary junction(APBJ)10 cases,and pancreatitis 10 cases.Resection of extrahepatic cyst with Roux-y hepaticojejunostimy was performed in 15 cases,preserving pylorus pancreatoduodinectomy in 1 case,and cholecystectomy and T tube drainage in 1 case.Excellent and good results were achieved on follow-up in 14 out of the 17 CCC cases undergoing surgical treatment,while pancreatitis occurred in 2 cases and unexpected death in 1 case.Conclusions Pancreatitis is apt to occurr in CCC with APBJ and bile pigment stone in choledochus.The incidence of pancreatitis in CCC and APBJ(P-B)can be decreased by resection of extrahepatic cyst and Roux-en-Y hepaticojejunostimy and cholecystectomy.

Objective To understand the successive dynamic change of population structure of Oncomelania hupensis during a one-year period,so as to provide the evidence for snail control. Methods A river beach and a ditch infested with O. hupensis snails were selected and longitudinally investigated in the midmonth during one year. The snail survey indices included the sur-vival status,gender,number of whorls,length and width of shell,and gonad development status(measured by the color depth of gonad and the length ratio of gonad to liver),and the monthly snail eggs in the soil were collected and counted simultaneous-ly. In addition,the temperature and humidity of the soil and the daily data of air temperature and precipitation were measured or collected during the study period(every month). Results Both survival rate of snails and live snail density at the two environ-ments were positively correlated with the temperatures of air and soil. With a slight bimodal distribution ,the snail survival rate peaked from May to June,and in September. The living snail densities got the highest level in July and September in the river beach,and from April to May in the ditch. The regression equations of snail length(L)and width(W)were Lbeach = 2.355 +1.678W(F=2989.43,P<0.01)and Lditch=0.478+2.091W(F=2.989.43,P<0.01),respectively. The snails were the ones with 4.07-11.81 mm in the length(8.98 ± 0.92)mm in the river beach,and the snails were the ones with 3.63-9.92 mm in the length(7.03 ± 0.82)mm in the ditch. The main snails were the ones with five to eight whorls of shell in the river beach and four to seven whorls of shell in the ditch. The proportions of snails with less than or equal to five whorls(in the river beach)and four (in the ditch)were the highest in May and September,about 20％. The ratios of male and female snails were 1.66 in the river beach and 1.22 in the ditch,respectively. The gonad development status of male and female snails was basically synchronous and had a bimodal abundance period-from April to May and September to October. The numbers of snail eggs in the soil among months were significantly different,reaching the highest in June in the river beach(100.8/0.1 m2),and May in the ditch(82.5/0.1 m2). Conclusion The principal periods of breeding and alternation of generations of snails are April-May and September-October every year,which should also be the optimal time for mollusciciding in schistosomiasis susceptible zones.

OBJECTIVETo construct enterohemorrhagic Escherichia coli (EHEC) O157: H7 ppk gene deletion strains and study its biological characteristics.

METHODSThe gene fragment of kanamycin resistance was amplified using a pair of homologous arm primers whose 5' and 3' ends were homologous with ppk gene and kanamycin resistance gene, respectively. EHEC O157: H7 EDL933w competent strains were prepared and transformed via electroporation with the amplification products. The ppk gene was replaced by kanamycin resistance gene using pKD46-mediated Red recombination system. The recombinant strain was confirmed by PCR and sequencing, and its morphology, growth ability and adhesion were assessed using Gram staining, OD600 value and Giemsa staining.

RESULTS AND CONCLUSIONWe established a ppk-deleted EHEC O157:H7 EDL933w strain with kanamycin resistance and compared the biological characteristics of the wild-type and mutant strains, which may facilitate further study of the regulatory mechanism of ppk gene.

DNA Primers ; Escherichia coli O157 ; genetics ; Escherichia coli Proteins ; genetics ; Gene Deletion ; Phosphotransferases (Alcohol Group Acceptor) ; genetics ; Polymerase Chain Reaction

OBJECTIVETo construct enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains with delection espF gene and its nucleotide fragment and with espF gene complementation.

METHODSA pair of homologous arm primers was designed to amplify the gene fragment of kanamycin resistance, which was transformed into EHEC O157:H7 EDL933w strain via the PKD46 plasmid by electroporation. The replacement of the espF gene by kanamycin resistance gene through the PKD46-mediated red recombination system was confirmed by PCR and sequencing. The entire coding region of espF along with its nucleotide fragment was amplified by PCR and cloned into pBAD33 plasmid, which was transformed into a mutant strain to construct the strain with espF complementation. RT-PCR was used to verify the transcription of espF and its nucleotide fragment in the complemented mutant strain.

RESULTS AND CONCLUSIONWe established EHEC O157:H7 EDL933w strains with espF gene deletion and with espF gene complementation. Both espF and its nucleotide fragment were transcribed in the complemented mutant strain. The two strains provide a basis for further study of the regulatory mechanism of espF.

Carrier Proteins ; genetics ; DNA Primers ; Escherichia coli O157 ; genetics ; Escherichia coli Proteins ; genetics ; Gene Deletion ; Plasmids ; Polymerase Chain Reaction