Structures of synthetic O-antigen fragments from serotype 2a Shigella flexneri in complex with a protective monoclonal antibody.

The anti-LPS IgG mAb F22-4, raised against Shigella flexneri serotype 2a bacteria, protects against homologous, but not heterologous, challenge in an experimental animal model. We report the crystal structures of complexes formed between Fab F22-4 and two synthetic oligosaccharides, a decasaccharide and a pentadecasaccharide that were previously shown to be both immunogenic and antigenic mimics of the S. flexneri serotype 2a O-antigen. F22-4 binds to an epitope contained within two consecutive 2a serotype pentasaccharide repeat units (RU). Six sugar residues from a contiguous nine-residue segment make direct contacts with the antibody, including the nonreducing rhamnose and both branching glucosyl residues from the two RUs. The glucosyl residue, whose position of attachment to the tetrasaccharide backbone of the RU defines the serotype 2a O-antigen, is critical for recognition by F22-4. Although the complete decasaccharide is visible in the electron density maps, the last four pentadecasaccharide residues from the reducing end, which do not contact the antibody, could not be traced. Although considerable mobility in the free oligosaccharides can thus be expected, the conformational similarity between the individual RUs, both within and between the two complexes, suggests that short-range transient ordering to a helical conformation might occur in solution. Although the observed epitope includes the terminal nonreducing residue, binding to internal epitopes within the polysaccharide chain is not precluded. Our results have implications for vaccine development because they suggest that a minimum of two RUs of synthetic serotype 2a oligosaccharide is required for optimal mimicry of O-Ag epitopes.

Failure of sterilization after clip placement.

BACKGROUND: Tubal sterilization is a common method of contraception used worldwide. The Filshie clip is a device designed to occlude the fallopian tubes. It is common practice to apply the clips across the isthmus using laparoscopy. It is often suggested that failures occur due to problems with the technique used to occlude the fallopian tubes. CASE: After insertion of an intrauterine device, a patient experienced an unplanned pregnancy and subsequent abortion. The intrauterine device was removed, and bilateral Filshie clips were applied by an experienced surgeon. After this procedure, the patient experienced a second unplanned pregnancy and subsequent abortion. A partial salpingectomy was performed after the fallopian tubes were examined, and it was confirmed that the Filshie clips were applied appropriately. CONCLUSION: It is important to understand why sterilization clips lead to contraceptive failure and to inform patients of this risk. Contraceptive failure after female sterilization remains a medical issue.

[Postoperative pain after hysterectomy through vaginal routes using electro surgical bipolar vessel sealing versus conventional suture ligature]. / Douleur postopératoire après hystérectomie par voie vaginale selon la méthode d'hémostase utilisée: thermofusion ou suture aux fils.

OBJECTIVES: The purpose of the study was to compare the postoperative pain of patients who had a hysterectomy through vaginal route according to the process of binding: wire or electrosurgical bipolar vessel sealing. PATIENTS AND METHODS: Retrospective study carried out in the 60 last patients who underwent a hysterectomy by vaginal route for a benign pathology in the gynaecological service of surgery of the CHI Poissy-Saint-Germain-en-Laye until March 2006. Among these patients, 32 had profited from a binding by wire and 28 of the electrosurgical bipolar vessel sealing. The studied criteria were the post-operative pain, total morphine consumption and the durations of the analgesic treatment, the hospitalisation and intervention time. RESULTS: The postoperative pain in the first 24 hours was twice lower using thermofusion; it was valid in immediate post-operative period and after 24 hours. In addition, total morphine consumption was also significantly lower using thermofusion. DISCUSSION AND CONCLUSION: This pilot study shows that the electrosurgical bipolar vessel sealing allows a reduction in the pain into the immediate postoperative period. Other prospective and randomised studies would allow it and conclude on the duration of hospitalisation, the quality of life from the patients and the cost in terms of public health.

[Laparoscopic repair of an incomplete post obstetrical uterine rupture. About one case]. / Réparation laparoscopique d'une rupture utérine incomplète post-obstétricale. A propos d'un cas.

The rate of incomplete uterine ruptures is unknown. These ruptures are usually asymptomatic but may cause chronic pelvic pain and/or intermenstrual bleeding. The conservative surgical repair techniques described in the literature are often practised by vaginal, combined (vaginal and laparoscopic) or hysteroscopic way. We propose an exclusive laparoscopic repair technique with satisfactory anatomical and functional short-term results.

[Prosthetic reinforcement by the vaginal approach after surgical repair of pelvic prolapse]. / Prise en charge des expositions de prothèse après cure de prolapsus génitaux par voie vaginale.

INTRODUCTION: Prosthetic reinforcement by the vaginal approach for surgical repair of pelvic prolapse is experiencing increasing popularity despite problems with tolerance. The most frequently described complication is prosthesis exposure, also known as erosion or granuloma. The mechanism is associated with defective vaginal healing and is independent of major infection such as pelvic cellulitis. OBJECTIVES: The purpose of our study was to define the course of this complication and the best therapeutic strategy for patients with prosthesis exposure. MATERIALS AND METHOD: Our continuous and retrospective study conducted over a period of 24 months between January 2002 and December 2003 recorded 34 files. These patients underwent prosthetic treatment via the vaginal approach of genital prolapse associated with prosthesis exposure. The procedure, known as TVM (Tension free Vaginal Mesh), involves the insertion without fixing of a synthetic prosthesis in areas of bladder-vagina and rectum-vagina detachment. RESULTS: In 33 cases out of 34, the exposure site was located on the anterior colpotomy scar (97%). These prosthesis exposures were managed in two stages, using antiseptic treatment first. This treatment cured 9 patients (26.47%). In the event of failure, a procedure was carried out under brief general anesthesia on an outpatient basis or during a 24-hour hospital stay. This single resection was sufficient for 20 patients (88%). Two patients nevertheless required a second removal procedure (8%) and one patient a third procedure (4%). To notice, one patient presented with a bladder-vagina fistula after resection. This observation of a bladder-vagina fistula following partial removal led us to recommend a blue test and/or cystoscopy as routine practice for each procedure. CONCLUSION: With this new vaginal approach for prolapse repair, it is important to monitor prosthesis exposure. To manage exposures, it is necessary to begin with antiseptic or estrogenic treatment. In the event of failure, a partial resection is warranted. We recommend careful prosthesis resection and systematic verification of the bladder.

[Risk factors for prosthesis exposure in treatment of genital prolapse via the vaginal approach]. / Facteurs de risque des expositions prothétiques après cure de prolapsus génital par voie vaginale.

OBJECTIVES: Prosthetic reinforcement in the surgical repair of pelvic prolapse by the vaginal approach is currently on the increase. However, this technique is not without tolerance-related problems. The most frequently described complication is prosthesis exposure, including erosion and delayed healing. It is independent of a granuloma and a major infection as pelvic cellulitis. Its mechanism is associated with defective vaginal healing. The purpose of our study is to define the risk factors for exposure of the prosthetic material. PATIENTS AND METHODS: Two hundred and seventy-seven medical records relating to patients undergoing surgery due to pelvic prolapse were included in our study. The treatment of genital prolapse was managed via the vaginal approach with polypropylene mesh. This is a continuous, retrospective study conducted over a period of 24 months. RESULTS: Thirty-four cases of prosthesis exposure were observed in the 2 months following surgery, which represents an incidence of 12.27%. The risk factors are concomitant hysterectomy [odds ratio 5.17 (P = 0.001)] and inverted T colpotomy [odds ratio 6.06 (P = 0.01)]. The protective factors are preservation of the uterus and the performance of a minor colpotomy in patients who had already undergone a hysterectomy or in those whose uterus had been preserved [odds ratio 5.16 (P = 0.0001)]. DISCUSSION AND CONCLUSION: In our study, we have only found risk factors of operative protocol. In fact, other information as age, menopause status or medical history of the patient is not significant. The uterus must be preserved and the number and extent of colpotomies needed to insert the prosthesis must be limited.

Molecular cloning and expression of two distinct human N-acetylgalactosamine 4-O-sulfotransferases that transfer sulfate to GalNAc beta 1-->4GlcNAc beta 1-->R in both N- and O-glycans.

Recently, cDNAs encoding human chondroitin 4-O-sulfotransferase-1 and -2 (C4ST-1 and C4ST-2) were cloned based on their similarity to HNK-1 sulfotransferase (HNK-1ST) (Hiraoka, N., Nakagawa, H., Ong, E., Akama, T.O., Fukuda, M.N., and Fukuda, M. [2000] Molecular cloning and expression of two distinct human chondroitin 4-O-sulfotransferases that belong to the HNK-1 sulfotransferase gene family. J. Biol. Chem., 275, 20188--20196). In the present study, we identified two additional novel sulfotransferases by searching the expression sequence tag and genomic DNA database for enzymes similar to C4ST-1 and C4ST-2. These newly cloned enzymes, termed GalNAc4ST-1 and GalNAc4ST-2, belong to the HNK-1ST gene family having 40--42% identity with C4ST-1. GalNAc4ST-1 and -2 do not add sulfate to HNK-1 precursor glycans, chondroitin, or desulfated dermatan sulfate. Instead, both enzymes can transfer sulfate to the 4-position of GalNAc in the context of GalNAc beta 1-->4GlcNAc beta 1-->R attached to both N-linked and core 2 branched O-linked oligosaccharides. GalNAc4ST-1 and -2 transcripts are highly expressed in the pituitary gland and trachea, respectively, and GalNAc4ST-1 and -2 transcripts are reciprocally expressed in other tissues as well. Moreover, both enzymes can transfer sulfate to lutropin, a pituitary glycoprotein hormone. These combined results indicate that GalNAc4ST-1 and -2 play critical roles in forming sulfo-->4GalNAc beta 1-->4GlcNAc beta 1-->R in both N-glycans and O-glycans in a tissue-specific manner.

Syntheses of chondroitin 4- and 6-sulfate pentasaccharide derivatives having a methyl beta-D-glucopyranosiduronic acid at the reducing end.

The syntheses are reported of beta-D-GlcpA-(1-->3)-beta-D-GalpNAc-(1-->4)-beta-D-GlcpA-(1- ->3)-beta-D-GalpNAc-(1-->4)-beta-D-GlcpA-(1-->OMe), O-sulfonated at C-4 or C-6 of the aminosugar moieties, which represent structural elements of chondroitin 4- and 6-sulfate proteoglycans. Starting from a synthetic disaccharide glycosyl acceptor, the stepwise or blockwise construction of the sugar backbone with appropriate synthons led to a pentasaccharide tetraol, which was used as a common intermediate. Selective 6-O-sulfonation of this tetraol, followed by saponification, gave the 6-sulfate derivative, whereas selective 6-O-benzoylation, followed by O-sulfonation and saponification, afforded the 4-sulfate derivative as their sodium salts.

Unexpected stereochemical outcome of activated 4,6-O-benzylidene derivatives of the 2-deoxy-2-trichloroacetamido-D-galacto series in glycosylation reactions during the synthesis of a chondroitin 6-sulfate trisaccharide methyl glycoside.

The synthesis of methyl (beta-D-glucopyranosyluronic acid)-(1-->3)-(2-acetamido-2-deoxy-6-O-sulfonato-beta-D-galactopyr anosyl)-(1-->4)-(beta-D-glucopyranosid)uronate trisodium salt, a chondroitin 6-sulfate trisaccharide derivative, is described. Loss of stereocontrol in glycosylation reactions involving activated 4,6-O-benzylidene derivatives of the 2-deoxy-2-trichloroacetamido-D-galacto series and D-glucuronic acid-derived acceptors was highlighted. This draw-back was overcome through the use of phenyl 3,4,6-tri-O-acetyl-2-deoxy-1-thio-2-trichloroacetamido-beta-D-gala ctopyranoside, which afforded the desired beta-linked disaccharide derivative in high yield with an excellent stereoselectivity. This later was submitted to acid-catalyzed methanolysis, followed by benzylidenation, and condensed with methyl 2,3,4-tri-O-benzoyl-1-O-trichloroacetimidoyl-alpha-D-glucopyran uronate to afford the expected trisaccharide derivative. Subsequent transformation of the N-trichloroacetyl group into N-acetyl, mild acid hydrolysis, selective O-sulfonation at C-6 of the amino sugar moiety, and saponification afforded the target molecule as its sodium salt in high yield.