Biomedical subjects
Publications and source records attributed to J Hamel.
Assessment of tarsometatarsal skeletal malalignment in congenital foot deformities such as clubfoot and vertical talus is possible with ultrasound. Sonography can be useful in deciding on the therapeutic concept and evaluating therapeutic effects.
Standardized sonographic delineation of the posterior tibial tendon using high-frequency ultrasonography with quantitative evaluation of the transverse section may confirm or exclude the clinical suspicion of posterior tibial tendon dysfunction and can serve as a complement to magnetic resonance imaging.
The localization and accessibility of the group B streptococcus (GBS) surface immunogenic protein (Sip) at the surface of intact GBS cells were studied by flow cytometric assay and immunogold electron microscopy. Antibodies present in pooled sera collected from mice after immunization with purified recombinant Sip efficiently recognized native Sip at the surfaces of the different GBS strains tested, which included representatives of all nine serotypes. Examination of GBS cells by immunogold electron microscopy revealed that the Sip-specific antibodies attached preferentially to polar sites and the septal region. This result confirmed that Sip is exposed at the intact-cell surface, but it also suggests that its distribution is restricted to certain regions of the cell.
The highly conserved NspA protein has been found in the outer membrane of every Neisseria meningitidis strain tested so far. Two monoclonal antibodies (MAbs) directed against this protein were used to demonstrate that biologically important epitopes of the NspA protein are exposed at the surface of serologically distinct meningococcal strains. Analysis of sera collected from mice that survived a deadly meningococcal challenge following immunization with recombinant NspA protein (rNspA) revealed the presence of cross-reactive antibodies which efficiently attached to and killed the four serogroup B strains tested. These data are additional proof that the NspA protein is exposed at the surface of intact meningococcal cells, which is an important characteristic for a vaccine candidate.
Nasal immunization was studied to determine if it could elicit an immune response capable of preventing vaginal colonization by Neisseria gonorrhoeae or of reducing its duration in the estradiol-treated mouse model. Nasal administration of gonococcal outer membrane (OM) preparations induced the development of systemic and vaginal immune responses that were directed mainly against a limited number of gonococcal OM proteins. The impact of nasal immunization on vaginal colonization by N. gonorrhoeae was evaluated by use of an experimental model, in which mice were treated with estradiol to prolong the infection. Bacterial clearance was significantly faster for mice immunized intranasally with N. gonorrhoeae OM preparations (4.0+/-2.5 days) than for control mice (8.5+/-4.3 days). The estradiol-treated mouse model may serve as a useful tool for the evaluation of potential gonococcal vaccine candidates.
Settlement and post-settlement processes of the sea cucumber Holothuria scabra Jaeger were studied in the laboratory. Independent and paired choice experiments revealed that several substrates could induce metamorphosis into pentactulae, but that specific substrates favoured settlement. Leaves of seagrass Thalassia hemprichii, with or without their natural bio-film, yielded the highest settlement rates (4.8-10.5%). T. hemprichii was preferred as a settlement substrate over sand, crushed coral, several other plant species and artificial seagrass leaves with or without a bio-film. Only settlement on the seagrass, Enhalus acoroides, was similar to that recorded for T. hemprichii. In the absence of a substrate, the larvae delayed settlement for nearly 96 h and survival was less than 0.5%. Sand and crushed coral, either alone or together, induced settlement from <1.5% of the available larvae. The pentactulae found on sand, coral and in bare containers were 10-35% smaller than those on T. hemprichii leaves. Soluble extracts from T. hemprichii and E. acoroides successfully induced metamorphosis and settlement on clean plastic surfaces. Newly settled juveniles remained on the seagrass leaves for 4-5 weeks before migrating to sand at around 6 mm in length. Prior to this, the juveniles spent 4-5 days moving on and off the leaves. Once on the sand, the juveniles became deposit-feeders, but did not show the typical burrowing behaviour of older specimens until they reached around 11 mm in length. The larvae of H. scabra appear to actively select seagrass leaves, possibly through chemical detection. We hypothesise that larvae settling on seagrass have an increased chance of growth and survival because they are provided with a suitable substrate on which to grow, and a bridge to sand substrates as they become deposit-feeders.
A protein of group B streptococci (GBS), named Sip for surface immunogenic protein, which is distinct from previously described surface proteins, was identified after immunological screening of a genomic library. Immunoblots using a Sip-specific monoclonal antibody indicated that a protein band with an approximate molecular mass of 53 kDa which did not vary in size was present in every GBS strain tested. Representatives of all nine GBS serotypes were included in the panel of strains. Cloning and sequencing of the sip gene revealed an open reading frame of 1,305 nucleotides coding for a polypeptide of 434 amino acid residues, with a calculated pI of 6. 84 and molecular mass of 45.5 kDa. Comparison of the nucleotide sequences from six different strains confirmed with 98% identity that the sip gene is highly conserved among GBS isolates. N-terminal amino acid sequencing also indicated the presence of a 25-amino-acid signal peptide which is cleaved in the mature protein. More importantly, immunization with the recombinant Sip protein efficiently protected CD-1 mice against deadly challenges with six GBS strains of serotypes Ia/c, Ib, II/R, III, V, and VI. The data presented in this study suggest that this highly conserved protein induces cross-protective immunity against GBS infections and emphasize its potential as a universal vaccine candidate.
The application of rotationplasty type B III (Winkelmann) for a patient with proximal femoral focal deficiency (PFFD) Pappas type II in a 5-year-old patient is described. The advantages for prosthetic management are discussed in comparison with other surgical options.
A low-molecular-weight protein named NspA (neisserial surface protein A) was recently identified in the outer membrane of all Neisseria meningitidis strains tested. Antibodies directed against this protein were shown to protect mice against an experimental meningococcal infection. Hybridization experiments clearly demonstrated that the nspA gene was also present in the genomes of the 15 Neisseria gonorrhoeae strains tested. Cloning and sequencing of the nspA gene of N. gonorrhoeae B2 revealed an open reading frame of 525 nucleotides coding for a polypeptide of 174 amino acid residues, with a calculated molecular weight of 18,316 and a pI of 10.21. Comparison of the predicted amino acid sequence of the NspA polypeptides from the gonococcal strains B2 and FA1090, together with that of the meningococcal strain 608B, revealed an identity of 93%, suggesting that the NspA protein is highly conserved among pathogenic Neisseria strains. The level of identity rose to 98% when only the two gonococcal predicted NspA polypeptides were compared. To evaluate the level of antigenic conservation of the gonococcal NspA protein, monoclonal antibodies (MAbs) were generated. Four of the seven NspA-specific MAbs described in this report recognized their corresponding epitope in 100% of the 51 N. gonorrhoeae strains tested. Radioimmunobinding assays clearly indicated that the gonococcal NspA protein is exposed at the surface of intact cells.
The cross-bactericidal and cross-protective activities of a monoclonal antibody (MAb) named Me-7, which is directed against an antigenically highly conserved epitope on the meningococcal NspA protein, were studied. This MAb efficiently killed in vitro, in the presence of rabbit or human serum, 13 of 14 meningococcal strains tested, including 9 of 9, 2 of 3, and 2 of 2 strains of serotypes B, A, and C, respectively. MAb Me-7 also significantly reduced by more than 75% the levels of bacteremia recorded for mice challenged with 10 of 11 meningococcal strains tested. Analysis of the predicted amino acid sequence of the NspA protein from the meningococcal strain MCH88 (A:4:P1.10), which was not killed by MAb Me-7, indicated the presence of an additional glutamine residue at position 73, compared to the three other NspA sequences. The data presented in this study suggest that antibodies directed against this highly conserved outer membrane protein could protect against meningococcal infections.
A new surface protein, named NspA, which is distinct from the previously described Neisseria meningitidis outer membrane proteins was identified. An NspA-specific mAb, named Me-1, reacted with 99% of the meningococcal strains tested indicating that the epitope recognized by this particular mAb is widely distributed and highly conserved. Western immunoblotting experiments indicated that mAb Me-1 is directed against a protein band with an approximate molecular mass of 22,000, but also recognized a minor protein band with an approximate molecular mass of 18,000. This mAb exhibited bactericidal activity against four meningococcal strains, two isolates of serogroup B, and one isolate from each serogroup A and C, and passively protected mice against an experimental infection. To further characterize the NspA protein and to evaluate the protective potential of recombinant NspA protein, the nspA gene was identified and cloned into a low copy expression vector. Nucleotide sequencing of the meningococcal insert revealed an ORF of 525 nucleotides coding for a polypeptide of 174 amino acid residues, with a predicted molecular weight of 18,404 and a isoelectric point of 9.93. Three injections of either 10 or 20 microg of the affinity-purified recombinant NspA protein efficiently protected 80% of the mice against a meningococcal deadly challenge comparatively to the 20% observed in the control groups. The fact that the NspA protein can elicit the production of bactericidal and protective antibodies emphasize its potential as a vaccine candidate.
In order to investigate whether pneumococcal heat shock proteins (HSPs) were major immunogens of humoral immune response, we first characterized the heat shock response of S. pneumoniae. Three HSPs, HSP62, HSP72 and HSP80, having an apparent molecular mass of 62, 72, and 80 kDa, respectively, were detected by labelling proteins synthesized with [35S]methionine after a shift from 37 degrees C to 45 degrees C and fluorography of SDS-polyacrylamide gels. Radioimmunoprecipitation and immunoblot analyses with mouse anti-pneumococcal sera revealed that HSP72 was a major immunogen. S. pneumoniae HSP62 was another antigen which was precipitated by some immune sera. Anti-HSP72 antibodies appeared after the first immunization with S. pneumoniae antigens and subsequent immunization elicited a booster response. Monoclonal antibodies (MAbs) to pneumococcal HSP72 were produced and their specificities defined. The epitopes reactive with four MAbs are highly conserved in S. pneumoniae since 20 out of 20 different strains were recognized by each individual MAb. Western blot analysis revealed cross-reactivities with few non-pneumococcal strains. By N-terminal sequence analysis, the S. pneumoniae HSP72 was found to belong to the heat shock protein 70 family. That HSP72 is an important highly conserved antigen in S. pneumoniae should provide a basis for further investigation of its physiological and potential pathogenic role.
GOAL OF SURGERY: Restoration of a plantigrade foot in adolescents suffering from a neurogenic foot deformity with an important, irreversible malposition of the talocalcaneonavicular joint complex. INDICATIONS: Severe, non reducible hindfoot deformity which cannot be corrected through soft tissue procedures alone. Important tarsal instability. Progressive forefoot deformities. CONTRAINDICATIONS: Presence of supple club foot deformities. Severe deformities necessitating removal of a bone wedge. Important degenerative changes of the subtalar joint. Presence of skin infection or sores. POSITIONING AND ANAESTHESIA: Supine with buttock of operated side slightly elevated. General or regional anaesthesia. Tourniquet at thigh. SURGICAL TECHNIQUE: Two skin incisions, one overlying the talonavicular and the other the calcaneoucuboid joint. Subperiosteal dissection until both approaches meet. Arthrodesis of the calcaneoucuboid and talonavicular joints after resection of articular cartilage and correction of deformity. Temporary fixation with Kirschner wires, visual control of correction and permanent fixation with titanium staples. Long leg cast which is split immediately. Additional tendon surgery may be necessary POSTOPERATIVE MANAGEMENT: Elevation of foot. Low molecular heparin. Well molded fibreglass cast after 2 weeks and heel added 2 weeks later. Orthopaedic shoes 10 to 12 weeks postoperatively. POSSIBLE COMPLICATIONS: Injury of neurovascular structures. Pressure sores. Thrombophlebitis. Wound dehiscence, deep infection. Displacement or breakage of staples. Absence of bony fusion. RESULTS: Between August 1990 and April 1993 the technique was performed 20 times in a total of 15 patients. Follow-up 14 to 36 months. A bony fusion occurred in all patients at 12 weeks. Eighteen times the functional result was good to satisfactory and these patients were free of pain. The following complications were observed: hindfoot varus (2), transient loss of sensation of foot (1), necrosis of the wound edges (2) and breakage of the staple (1).
We report a new diagnostic imaging technique for talipes equinovarus. Sonographic assessment of the medial border of the foot offers insight into the center of tarsal malalignment at the talonavicular joint. Technique, observations, and interpretation of the findings are delineated and compared with current radiologic evaluation of talonavicular alignment according to the method of Simons in 38 cases. The TnCE-angle is introduced as a sonographic measure to quantify talonavicular malalignment in clubfeet. Sonographic results of clubfeet are compared with those of a group of 98 normal feet. The practical implications of the method as a means for planning and control of treatment in clubfoot deformity are discussed.
This study deals with a combined bony and soft-tissue procedure (Grice-Schede) for the treatment of pes (equino) planovalgus in children suffering from cerebral palsy. Results of 43 treated feet in 28 children were assessed clinically and radiologically at a mean follow-up time of 6.7 years (range from 0.6 years to 13.8 years). In all, 58.1% excellent or good results, 14.0% satisfactory and 27.9% poor results were found. The procedure can be recommended for patients with hemiplegic and diplegic conditions. It is not suited for patients with total body involvement.
In this study, it has been determined that immunoglobulin G1 (IgG1) and IgG3 monoclonal antibodies directed to the lipooligosaccharide A of Bordetella pertussis were able to protect mice from fatal aerosol infection. No correlation was found between the bactericidal activity in vitro in the presence of complement and the protection in mice, since a bactericidal IgG3 did not elicit protection. In addition, no significant difference in protective capacity was observed with bactericidal and nonbactericidal IgG1 antibodies, indicating that bactericidal activity is not a requirement for protection mediated by certain anti-lipooligosaccharide A antibodies. A reduction in protection in C5-deficient mice was observed, suggesting a significant role for complement in certain host defense mechanisms against B. pertussis infection.
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We have developed a novel enzyme immunoassay (EIA) for the specific detection of Chlamydia trachomatis utilizing a monoclonal anti-idiotypic antibody to an antibody directed against a chlamydia specific epitope on 60 kDa heat-shock protein (HSP60). The basis of the assay is the inhibition of the binding of idiotype to anti-idiotype by antigen present in test samples. Two configurations of the assay were developed: a blocking EIA and a competition EIA. Greater sensitivity was observed using the competition EIA, with the assay detecting purified recombinant HSP60 and purified chlamydia in a concentration-dependent manner from 0.01 to 10 micrograms protein and from 0.5 to 12 micrograms total protein, respectively. The assay is highly specific and offers several potential advantages over currently available EIAs for the detection of this pathogen.