ABSTRACT
PURPOSE: To assess the value of single shot fast spin echo MR sequence (SS-FSE) in the morphological analysis of the biliary tree and pancreatic ducts and to compare its accuracy with other imaging methods. MATERIAL AND METHODS: 95 consecutive patients referred for clinical and/or biological suspicion of biliary obstruction were explored with MR cholangiopancreatography (MRCP). All patients were explored with a Signa 1.5 T GE MR unit, with High Gradient Field Strength and Torso Phased Array Coil. Biliary ducts were explored with SS-FSE sequence, coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Total acquisition time was 1 second. Native pictures were reviewed by two radiologists blinded to clinical information. In case of disagreement, a third radiologist's judgement was requested. In 88 cases, MRCP results were compared with direct biligraphy methods. RESULTS: In all cases, MRCP produced high quality images without MIP or other post-processing methods. For detection of biliary tree distensions, the concordance value of MRCP was over 91% (Kappa 0.82). For detection of biliary tree and/or pancreatic duct obstruction, MR sensitivity was 100% and specificity 91%. The overall diagnostic concordance value of MRCP was > or = 93%. Difficulties in MRCP were caused by functional diseases or benign stenosis. MRCP accurately diagnosed all lithiasic obstructions starting from a stone size of 3 mm. CONCLUSION: MRCP produces fastly high-quality images. As it is totally safe, it can be proposed as a first intention method in biliopancreatic duct explorations.
Subject(s)
Bile Duct Diseases/diagnosis , Magnetic Resonance Imaging/methods , Pancreatic Diseases/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Bile Duct Diseases/diagnostic imaging , Calculi/diagnosis , Calculi/diagnostic imaging , Cholangiography , Cholangiopancreatography, Endoscopic Retrograde , Cholelithiasis/diagnosis , Cholelithiasis/diagnostic imaging , Cholestasis/diagnosis , Cholestasis/diagnostic imaging , Constriction, Pathologic/diagnosis , Constriction, Pathologic/diagnostic imaging , Female , Humans , Image Processing, Computer-Assisted/methods , Male , Middle Aged , Pancreatic Diseases/diagnostic imaging , Pancreatic Ducts/diagnostic imaging , Pancreatic Ducts/pathology , Sensitivity and Specificity , Single-Blind MethodABSTRACT
Agrobacterium vitis is a common pathogen of grapevine. Most strains utilize tartrate, an abundant compound in grapevine. Strain AB3 carries two tartrate utilization (or TAR) regions: TAR-I (on the large pTrAB3 plasmid) and TAR-II (on the AB3 Ti plasmid). TAR-I and TAR-II were structurally and functionally analyzed and are similar to the TAR-III region from the tartrate utilization plasmid pTrAB4 of the nopaline-type A. vitis strain AB4 (Crouzet and Otten, J. Bacteriol. 1995, 177:6518-6526). The minimal tartrate utilization region of TAR-I contains four genes (ttuA-ttuD). The ttuC gene is homologous to the tartrate dehydrogenase gene from Pseudomonas putida. Outside the minimal region a second ttuC-like gene is found (ttuC') which is transcribed and complements a ttuC mutant. Most grapevine isolates carry one or two of the three characterized TAR regions and show a considerable degree of polymorphism around these regions.
Subject(s)
Genes, Bacterial , Rhizobium/genetics , Rhizobium/metabolism , Tartrates/metabolism , DNA Mutational Analysis , DNA, Bacterial/chemistry , Fruit/microbiology , Molecular Sequence Data , Mutagenesis, Insertional , Open Reading Frames , Plant Diseases , Plasmids , Restriction Mapping , Rhizobium/pathogenicityABSTRACT
The grapevine is the natural host of the tumorigenic bacterium Agrobacterium vitis. Most of the A. vitis isolates can use tartrate, an unusually abundant compound in grapevine. The nopaline strain, AB4, contains a 170-kb conjugative plasmid (pTrAB4) encoding tartrate utilization. A 5.65-kb pTrAB4 region which enables non-tartrate-utilizing Agrobacterium tumefaciens to grow on tartrate was sequenced and mutagenized with the transcriptional fusion transposon Tn5-uidA1. This DNA fragment contains four intact open reading frames (ORFs) (ttuABCD) required for tartrate-dependent growth. The mutant phenotypes of each ORF, their homologies to published sequences, and their induction patterns allowed us to propose a model for tartrate utilization in A. vitis. ttuA encodes a LysR-like transcriptional activator and is transcribed in the absence of tartrate. ttuB codes for a protein with homology to transporter proteins and is required for entry of tartrate into bacteria. ttuC codes for a tartrate dehydrogenase, while ttuD lacks homology to known sequences; the growth properties of ttuD mutants suggest that TtuD catalyzes the second step in tartrate degradation. A fifth incomplete ORF (ttuE) encodes a pyruvate kinase which is induced by tartrate and required for optimal growth. Although the ttuABCD fragment allows growth of A. tumefaciens on tartrate, it does not provide full tartrate utilization in the original A. vitis background.
Subject(s)
Operon/genetics , Rhizobium/genetics , Tartrates/metabolism , Amino Acid Sequence , Bacterial Proteins/genetics , Base Sequence , Culture Media , DNA Mutational Analysis , DNA, Bacterial/genetics , Gene Expression Regulation, Bacterial/drug effects , Molecular Sequence Data , Mutagenesis, Insertional , Open Reading Frames/genetics , Plasmids/genetics , Restriction Mapping , Rhizobium/enzymology , Rhizobium/growth & development , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Stereoisomerism , Tartrates/pharmacologyABSTRACT
The vitopine Ti plasmid pTiS4 of Agrobacterium vitis has an unusual T-DNA organization. The pTiS4 oncogenes, localized by screening selected pTiS4 clones for growth-inducing activity, are localized on three T-DNAs, whereas in all other characterized Ti plasmids one or two T-DNAs are found. The nucleotide sequences and predicted amino acid sequences of the pTiS4 oncogenes set them apart from the corresponding genes from other Ti or Ri plasmids. The oncogenes induce the same type of reaction on various test plants as the well-known pTiAch5 oncogenes but the pTiS4 ipt gene induces considerably more shoots than its Ach5 homologue. We have also identified the gene coding for vitopine synthase as well as a vitopine synthase pseudogene. Both sequences show homology to the octopine synthase gene. In terms of both nucleotide sequence and overall organization, the pTiS4 T-DNAs appear to be only distantly related to previously characterized T-DNAs.
