Salmonella genomic island 1-J variants associated with change in the antibiotic resistance gene cluster in multidrug-resistant Salmonella enterica serovar Virchow isolated from humans, Taiwan, 2004-2006.

Salmonella genomic island 1 (variant SGI1-J3) has been previously identified in multi-drug resistant (MDR) Salmonella enterica serovar Virchow isolated from humans in 1994. In this study, antimicrobial resistance, genotypes and genetic relationship were investigated in 96 S. Virchow isolates collected from humans in 2004-2006. XbaI-PFGE analysis separated 96 isolates into two main related clusters, I and II, which consisted of four major pulsotypes differing in prevalence by year. The majority of isolates were MDR to chloramphenicol, sulfonamide, trimethoprim and tetracyclines associated with antimicrobial resistance genes dfrA1, floR2, sulI and tet(G) of variant SGI1-J3. Among nine variants, we determined two novel variants, SGI1-J4 and -J5, which have undergone different homologous recombinational events resulting in partial deletions of the MDR region. The first one contained an empty integron structure and the second presented a deletion extending from the IS6100 element to the adjacent SGI1 backbone. SGI1-J3 is largely encountered in clonally related MDR S. Virchow isolates collected from humans, which spread vertically. The genomic island SGI1 appears to be largely responsible for the diversity of MDR phenotypes among S. Virchow isolates in Taiwan.

The C terminus of lettuce mosaic potyvirus cylindrical inclusion helicase interacts with the viral VPg and with lettuce translation eukaryotic initiation factor 4E.

Recessive resistance to lettuce mosaic virus (LMV) is conferred in lettuce by the mo1 gene, encoding the eukaryotic translation initiation factor 4E (eIF4E). The C terminus of the viral cylindrical inclusion helicase (CI-Cter), together with the VPg, is involved directly in overcoming mo1 resistance. In this study, recombinant LMV VPg and CI-Cter proteins from wild-type or resistance-breaking isolates were expressed and purified from Escherichia coli. The allelic forms of eIF4E from susceptible or resistant lettuce cultivars were produced similarly and these proteins were used in ELISA-based assays to demonstrate the in vitro binding of the various forms of LMV CI-Cter to both lettuce eIF4E and LMV VPg proteins. All combinations tested displayed significant and specific interactions, and the interaction between the C-terminal part of the LMV CI and eIF4E was confirmed in vivo in bimolecular fluorescence complementation assays. Higher interaction signals for both CI-eIF4E and CI-VPg were observed for LMV-E, indicating that the eIF4E interaction network involving CI and VPg appears to be stronger in the case of this resistance-breaking isolate. This could suggest the need for a minimal interaction threshold for infection success in resistant lettuce, but more precise measurement of the interaction parameters linking eIF4E, VPg and CI is needed in order to reinforce such a hypothesis.

[Dna ploidy in adenocarcinoma of Barrett's esophagus]. / Etude de l'ADN-ploïdie dans les adénocarcinomes sur endobrachyoesophage.

We have studied by flow cytometry the ADN-ploidy of 23 adenocarcinomas developed on Barrett's oesophagus operated at hospital Beaujon between 1982 and 1988. This retrospective study was done on formalin-fixed and paraffin-embedded material. Non dysplastic Barrett's mucosa was diploid in all of the 11 studied cases. Dysplastic mucosa was aneuploid in the 4 studied cases, as were the carcinomas in the same patients. Seven tumors were diploid, and 16 aneuploid. There was no relationship between the aneuploidy and the degree of tumor differentiation. Fourteen of the 15 tumors which invaded the adventitia and only 2 of the 8 tumors which were limited to the muscularis propria were aneuploid. Thirteen of 16 aneuploid and only 2 of 7 diploid tumors had lymph node invasion. Six of the 7 patients with diploid tumor were well 12 to 52 months after surgery. Eleven of the 16 patients with aneuploid tumor died, the remaining 5 were well 12 to 18 months after surgery. The ratio of aneuploid adenocarcinomas developed on Barrett's oesophagus is similar to the ratio observed in other types of solid tumors. The prognosis of adenocarcinoma in Barrett's oesophagus is poor. According to our results, the prognosis of diploid tumors seems to be better than that of aneuploid tumors. In order to determine the value of ADN-ploidy as an independent prognostic criterion, it would be of interest to study a greater number of patients with longer follow-up.

[Hemorrhagic rectocolitis and carcinoma of the colon. Contribution of flow cytometry. Report of 3 cases]. / Rectocolite hémorragique et carcinome colique. Données de la cytométrie en flux. A propos de trois observations.

Carcinoma complicating ulcerative colitis, although an uncommon event, is well known but follow-up of patients to detect high-grade dysplasia as a potential indicator for colectomy is very difficult. Retrospective morphological and cytometrical analysis of three resected colons harboring carcinoma coming from patients with ulcerative colitis were performed. It allowed to confirm the value of this technique. Histogram patterns varied between narrow unimodal in quiescent mucosa to broad unimodal with high IP (proliferation index) in regenerative mucosa and aneuploid in high dysplasic mucosa and carcinoma. In addition to histopathology and in spite of a patchy distribution of aneuploidy, different degrees of dysplasia in mucosa and technical sensibility DNA (desoxyribonucleic acid) analysis in long-standing ulcerative colitis seems to be helpful in the detection of potential malignancy.

[Flow cytometry of polypoid neoplasms of the colon resected by endoscopy]. / Etude en cytométrie de flux des néoplasies polypoïdes du côlon réséquées par endoscopie.

Sixty-one neoplastic polypoid lesions of the large bowel and rectum, obtained by endoscopic resection, were submitted to cytofluorometric measurements. This study was performed on archival formalin fixed and paraffin embedded material using the method of Hedley. Coefficient of variation, DNA Index, DNA aneuploidy, proliferative activity were statistically correlated to histological grading (according to U.I.C.C.) and to the presence of trophic changes (epithelial displacement, hemorrhage, mucus discharge. Compared with morphological findings, cytofluorometric results revealed that DNA aneuploidy appeared only when intraepithelial carcinomatous changes were present, and was found in 50 percent of microinvasive carcinoma. The proliferative activity was significantly increased in intraepithelial carcinomas, with a significant enlargement of the coefficient of variation. This change may reflect initial disorders in DNA content of neoplastic cells. On the other hand, there was no significant difference between lesions with and without trophic alterations. These findings confirm that this increase is an independent phenomenon during tumor progression.