Biomedical subjects

C Lefevre

Publications and source records attributed to C Lefevre.

At least 19 recordsLinked to original sources

PubMed2006

Characterization of two whey protein genes in the Australian dasyurid marsupial, the stripe-faced dunnart (Sminthopsis macroura).

We report the first isolation and sequencing of genomic BAC clones containing the marsupial milk protein genes Whey Acidic Protein (WAP) and Early Lactation Protein (ELP). The stripe-faced dunnart WAPgene sequence contained five exons, the middle three of which code for the WAPmotifs and four disulphide core domains which characterize WAP. The dunnart ELPgene sequence contained three exons encoding a protein with a Kunitz motif common to serine protease inhibitors. Fluorescence in situ hybridization located the WAPgene to chromosome 1p in the stripe-faced dunnart, and the ELPgene to 2q. Northern blot analysis of lactating mammary tissue of the closely related fat-tailed dunnart has shown asynchronous expression of these milk protein genes. ELPwas expressed at only the earlier phase of lactation and WAPonly at the later phase of lactation, in contrast to beta-lactoglobulin (BLG) and alpha-lactalbumin (ALA) genes, which were expressed in both phases of lactation. This asynchronous expression during the lactation cycle in the fat-tailed dunnart is similar to other marsupials and it probably represents a pattern that is ancestral to Australian marsupials.

Animals↗

PubMed2005

Sequencing and mapping hemoglobin gene clusters in the Australian model dasyurid marsupial Sminthopsis macroura.

Comparing globin genes and their flanking sequences across many species has allowed globin gene evolution to be reconstructed in great detail. Marsupial globin sequences have proved to be of exceptional significance. A previous finding of a beta(beta)-like omega(omega) gene in the alpha(alpha) cluster in the tammar wallaby suggested that the alpha and beta cluster evolved via genome duplication and loss rather than tandem duplication. To confirm and extend this important finding we isolated and sequenced BACs containing the alpha and beta loci from the distantly related Australian marsupial Sminthopsis macroura. We report that the alpha gene lies in the same BAC as the beta-like omega gene, implying that the alpha-omega juxtaposition is likely to be conserved in all marsupials. The LUC7L gene was found 3' of the S. macroura alpha locus, a gene order shared with humans but not mouse, chicken or fugu. Sequencing a BAC contig that contained the S. macroura beta globin and epsilon globin loci showed that the globin cluster is flanked by olfactory genes, demonstrating a gene arrangement conserved for over 180 MY. Analysis of the region 5' to the S. macroura epsilon (epsilon) globin gene revealed a region similar to the eutherian LCR, containing sequences and potential transcription factor binding sites with homology to eutherian hypersensitive sites 1 to 5. FISH mapping of BACs containing S. macroura alpha and beta globin genes located the beta globin cluster on chromosome 3q and the alpha locus close to the centromere on 1q, resolving contradictory map locations obtained by previous radioactive in situ hybridization.

Animals↗

PubMed2002

Bone morphing: 3D morphological data for total knee arthroplasty.

OBJECTIVE: The clinical outcome of a total knee arthroplasty (TKA) is mainly determined by the accuracy of the surgical procedure itself. To improve the final result, one must take into account (a) the alignment of the prosthesis with respect to the mechanical axis, and (b) the balance of the soft tissues. Therefore, morphologic data (such as the shape of the epiphysis) and geometric data are essential. We present a new method for performing TKA based on morphologic and geometric data without preoperative images. MATERIALS AND METHODS: The global method is based on the digitization of points with an optical 3D localizer. For the morphologic acquisitions, we use a method based on the registration of sparse point data with a 3D statistical deformable model. To build the mechanical axis, we use a kinematics method for the hip center and digitization of anatomical landmarks for the ankle centers. The knee center is not determined by digitization or kinematics of the knee, as this would not be accurate. The surgical planning relies totally on the soft-tissue balance, which is the key issue for a good kinematics result. RESULTS: We have used this system for 6 months in a randomized clinical trial involving 35 patients to date. For the first 11 patients that could be measured in the navigation group, the postoperative frontal alignment was within the range of 180 +/- 3 degrees. Fluoroscopic assessment of the soft-tissue balancing will be performed at the conclusion of an extended 2-year study to evaluate the results from a functional point of view. CONCLUSION: Bone Morphing is an accurate, fast, and user-friendly method that can provide morphologic as well as geometric data. We have introduced the important notion of soft-tissue balancing into the intraoperative planning step to optimize the kinematics as well as the anatomy. Therefore, this method should be considered as an alternative to the CT-based method.

Algorithms↗

PubMed2002

[Long gamma nail for the treatment of subtrochanteric fracture of the femur].

PURPOSE OF THE STUDY: The standard gamma nail is commonly used for the treatment of trochanteric fractures but cannot be used if the fracture lies at the level of the distal locking. Theoretically, the long gamma nail would overcome this inconvenience and could be used for all cases of subtrochanteric and trochanteric-shaft fractures. MATERIAL AND METHODS: Clinical and radiological charts were established in 1990 for a multicentric study. The radiology work-up included an AP view of the pelvis and an oblique lateral view of the hip. Two classifications were used: Seinsheimer and Muller as modified by Nazarian. Three stages of fracture reduction were recorded: 1=anatomic reduction, 2=acceptable reduction, 3=poor reduction. From January 1995 to December 1999, 46 patients were treated with the long gamma nail. Twenty-four cases were excluded for various reasons (from which 3 early death). 22 remaining patients were followed for more than six months. Mean age was 68 years (range 42-96); there were six women and 16 men. Ten patients were traffic or work accident victims and 12 had had a home accident. RESULTS: Mean duration of surgery was 70 minutes. Three patients required revision surgery within a week of the initial osteosynthesis. Mean hemoglobin level before surgery was 12.9 g/dl; 8.9 g/dl during the first postoperative week. Mean hospital stay was 14 days. Weight-bearing with support was possible early after surgery in 16 patients who walked with crutches or a walker. Mean delay to weight-bearing was 11 days. At three months, all patients were using an aid for walking; at six months, four patients used a walker. Bone healing was achieved on the average at the twelfth week. Radiological reduction was anatomic in four, acceptable in three and poor in 15. DISCUSSION: We advocate the AO classification as it allows a structured analysis of all fractures within a unique system. We compared our results with nine series reported in the literature using other therapeutic methods (screw-plate, nail-plate, Ender nail). The operative time for the long gamma nail (70 min) was comparable with that for other surgical techniques. Treatment with the long gamma nail favors bone healing and limits the risk of infection. Radiological results in our series were poor, but there were no cases with nonunion and the morbidity was low.

Adult↗

PubMed2001

The use of MR images to evaluate the risks associated with proximal locking of intramedullary tibial nails.

Vascular complications associated with locked intramedullary tibial nailing are infrequent but always serious, with a secondary amputation rate of 30%. These complications, based on an MR study of the anatomic relationships between the interlocking screws and the neurovascular or articular structures at the proximal end of the tibia, have been analysed. Two types of nails were used: one with anterior-posterior locking and a specially designed prototype with oblique locking. In particular this study emphasised the anatomic risk of injury to the popliteal structures when using anterior-posterior locking, as well as to the anterior tibial vessels and proximal tibiofibular joint when using oblique locking. As no locking method appears to be better than any other, the best is that associated with the lowest morbidity. Consequently, the use of frontal instead of anterior-posterior locking is recommended; the use of oblique locking, which this study has shown carries a much higher risk of complications, is strongly advised against.

Bone Nails↗

PubMed2001

Pedicle island flaps of latissimus dorsi. Applications in surgical repair of ruptures of the rotator cuff.

There are considerable problems in repair of major ruptures of the rotator cuff tendons particularly those of the supra and infraspinatus mm. The Gerber technique only transfers the tendinous insertion of the latissimus dorsi onto the greater tuberosity in massive cuff ruptures. We have extended this approach. In 12 shoulders, we studied the feasibility of a latissimus dorsi transfer harvested to fit and bearing muscle and tendon detached at its two extremities and transposed as a neurovascular island. The muscular part is transferred to the infra or supraspinous fossae and the tendon to the greater tuberosity with the aim of reactivating the infra and supraspinatus muscles. The lateral bundle of the latissimus dorsi is always transferable on its neurovascular pedicle into the infraspinous fossa, even into the supraspinous fossa, or into both if transfer is used as a bilobed flap. This anatomical work allowed a parallel study of the different possibilities of transposing the neurovascular pedicle, which might limit the technique, and also to determine the most appropriate surgical approach.

Adult↗

PubMed1999

[Bilateral bipartite carpal scaphoid bone: a congenital disease or unrecognized pseudarthrosis? Discussion a propos of a clinical case].

PURPOSE OF THE STUDY: Bipartite scaphoid has long been debated, and is of traumatic origin for some authors or congenital for others. The aim of the study is to distinguish clinical and radiographic criteria for the diagnosis of congenital bipartite scaphoid. MATERIAL AND METHOD: A case of bilateral bipartite scaphoid is presented. To distinguish pseudarthrosis from congenital bipartite scaphoid we used, the revised carpal height ratio of Nattrass, the CT, and magnetic resonance imaging. RESULTS: These examinations showed no collapse and they revealed evidence of articular cartilage around the fragments with the same thickness in all the carpus. CONCLUSION: We believe that congenital origin is more probable but we recommend to follow the patient, with yearly standard wrist radiograph and use, the revised carpal height ratio of Nattrass to research a carpal shift or collapse.

Adult↗

PubMed1998

New susceptibility locus for rheumatoid arthritis suggested by a genome-wide linkage study.

Rheumatoid arthritis (RA), the most common autoimmune disease, is associated in families with other autoimmune diseases, including insulin-dependent diabetes mellitus (IDDM). Its genetic component has been suggested by familial aggregation (lambdas = 5), twin studies, and segregation analysis. HLA, which is the only susceptibility locus known, has been estimated to account for one-third of this component. The aim of this paper was to identify new RA loci. A genome scan was performed with 114 European Caucasian RA sib pairs from 97 nuclear families. Linkage was significant only for HLA (P < 2.5.10(-5)) and nominal for 19 markers in 14 other regions (P < 0.05). Four of the loci implicated in IDDM potentially overlap with these regions: the putative IDDM6, IDDM9, IDDM13, and DXS998 loci. The first two of these candidate regions, defined in the RA genome scan by the markers D18S68-D18S61-D18S469 (18q22-23) and D3S1267 (3q13), respectively, were studied in 194 additional RA sib pairs from 164 nuclear families. Support for linkage to chromosome 3 only was extended significantly (P = 0.002). The analysis of all 261 families provided a linkage evidence of P = 0. 001 and suggested an interaction between this putative RA locus and HLA. This locus could account for 16% of the genetic component of RA. Candidate genes include those coding for CD80 and CD86, molecules involved in antigen-specific T cell recognition. In conclusion, this first genome scan in RA Caucasian families revealed 14 candidate regions, one of which was supported further by the study of a second set of families.

Arthritis, Rheumatoid↗

PubMed1997

A novel tandem repeat sequence located on human chromosome 4p: isolation and characterization.

In an effort to analyze the genomic region of the distal half of human chromosome 4p, to where Huntington disease and other diseases have been mapped, we have isolated the cosmid clone (CRS447) that was likely to contain a region with specific repeat sequences. Clone CRS447 was subjected to detailed analysis, including chromosome mapping, restriction mapping, and DNA sequencing. Chromosome mapping by both a human-CHO hybrid cell panel and FISH revealed that CRS447 was predominantly located in the 4p15.1-15.3 region. CRS447 was shown to consist of tandem repeats of 4.7-kb units present on chromosome 4p. A single EcoRI unit was subcloned (pRS447), and the complete sequence was determined as 4752 nucleotides. When pRS447 was used as a probe, the number of copies of this repeat per haploid genome was estimated to be 50-70. Sequence analysis revealed that it contained two internal CA repeats and one putative ORF. Database search established that this sequence was unreported. However, two homologous STS markers were found in the database. We concluded that CRS447/pRS447 is a novel tandem repeat sequence that is mainly specific to human chromosome 4p.

Animals↗

PubMed1997

[Use of muscular flaps for the treatment of open fractures of limbs. Apropos of 42 cases].

PURPOSE OF THE STUDY: Since 1988, skin defect associated with upper (6 cases) or lower (34 cases) limb fractures were treated in our Orthopaedic Department with regional or free muscular flaps. The aim of this study was to demonstrate that muscular flaps represent a treatment of choice for infection prevention and consolidation. MATERIAL AND METHODS: 42 patients have been treated: 29 Cauchoix III or IV, 12 secondary exposed fractures, 1 amputation. A total of 42 flaps, including 28 regional flaps and 14 microvascular free-tissue transfers were performed. A first stage included thorough debridement, fixation with external fixator in 85 per cent, and revascularization (4 cases). A second look was necessary in all but 3 cases: flap coverage was performed at this stage. A bone graft was proposed in 17 cases after a mean time of 3 months and 20 days. RESULTS: Bony healing was found in 37 cases (86.5 per cent) with a mean delay of 7 months 20 days. 5 patients required another method of treatment because of flap necrosis or non-union, with an average time to bony healing of 13 months. 42 tissue transfers were performed with an overall success rate of 95.3 per cent (2 necrosis of latissimus dorsi flaps). 3 partial necrosis involved 2 regional and 1 free flap. One of them needed another treatment. No infection was encountered in 40 cases (95 per cent) even if most of the patients were treated after initial treatment elsewhere. DISCUSSION: Experience with regional muscle transfer has advocated the gastrocnemius and proximal pedicle medial soleus as reliable and excellent choice for reconstruction of the proximal and middle third of the leg. Latissimus dorsi transfer, which can be used totally, partially, or as a "vascular graft flap" represent the treatment choice for extensive upper or lower limb exposed fracture especially for distal lower limb fracture (exposure of the tibia). Muscle flap coverage in the acute period (within 48 or 72 hours) remains for us the best treatment.

Adolescent↗

PubMed1997

Osteoarthritis of the pisiform-triquetral compartment. A review of eight cases of an underrecognized entity.

Seven patients (eight hands) with pain suggestive of the pisiform-triquetral compartment were studied to compare outcomes after surgical excision of the pisiform (four hands) and after conservative therapy (four hands). All patients were reevaluated by a rheumatologist who was not involved in their treatment. The efficacy of conservative therapy was mediocre in every case. Although it is reasonable to assume that the surgically-treated patients had more severe manifestations at baseline, all were free of symptoms at reevaluation, versus none of the conservatively-treated patients. After two years, excision of the pisiform yielded excellent results with no adverse effects on range of motion or grip strength. Despite the small size of our sample and the relatively low incidence of pisitriquetral osteoarthritis, our data suggest that surgery is preferable over conservative therapy in this condition.

Aged↗

PubMed1997

[Surgical treatment of freshly closed articular fractures of proximal interphalangeal joints].

Eleven fractures of the base of P2 and 8 fractures of the head of P1 were treated surgically. We review the results after a mean follow-up of 4 years 5 months. Due to their complexity is no real consensus on the treatment of P2 and various treatments were used. This series demonstrated two points: first the was no correlation between the degree of patient satisfaction and the section of digital immobilization; second, residual subluxation and/or arthrosic remodeling was frequent but was not incompatible with a good objective and subjective outcome.

Adult↗

PubMed1996

[Surgery of congenital radio-ulnar synostosis. Technical error and therapeutic strategy].

PURPOSE OF THE STUDY: A clinical feature of surgery in congenital radioulnar synostosis is described. MATERIAL AND METHODS: A eighteen year old right handed woman, was hampered when she works by a left congenital radio ulnar synostosis. Clinical examination showed a left forearm locked in 75 degrees of pronation. Radiographs showed a proximal synostosis. Surgical treatment associated a resection of the synostosis with silastic interposition, resection of the distal end of the ulna, and derotational middle-third osteotomy of the radius. RESULTS: Three months later, the pronosupination was 90 degrees, but an ischemic retraction of the flexor pollicis longus muscle appeared with a non-union of the radius. A second procedure was necessary to put a plate in compression on bone and to release the muscle. Twenty years later, the forearm was locked in neutral pronosupination, without recurrence of synostosis on radiographs. DISCUSSION: Surgical treatment in congenital radio ulnar synostosis associates many problems: indication (often for discomfort), ideal age (more vascular or nervous post operative complications if older), technical (failure of operations with functional aim). CONCLUSION: A review of international litterature allows the authors to suggest a specific management for congenital radio ulnar synostosis.

Adolescent↗

PubMed1995

[Kirner's deformity. 4 case reports and review of the literature].

Kirner's disease is a rare deformity of the distal phalanx of the little finger, with a combination of camptodactyly and clinodactyly and clinodactyly. A review of the literature and analysis of our cases show that this anomaly appears to result from a unusual insertion of the deep flexor over the growth cartilage. No treatment is required in view of the absence of any clinical and functional symptoms.

Adolescent↗

PubMed1995

[Flaps of the gastrocnemius muscles].

The authors expose different techniques and maneuvers used for dissection of gastrocnemius flaps with reference to the data reported in the literature and to the anatomical vascular basis. The use of muscular and myocutaneous gastrocnemius flaps and some modifications of the standard surgical technique aiming to gain more versatility are described, so that, the range of these flaps can be planned to cover the greatest part of the lower extremity of the leg.

Humans↗

PubMed1994

Assignment of the protonated 13C resonances of apo-neocarzinostatin by 2D heteronuclear NMR spectroscopy at natural abundance.

Nearly complete assignment of the protonated carbon resonances of apo-neocarzinostatin, a 113-amino acid antitumor antibiotic carrier protein, has been achieved at natural 13C abundance using heteronuclear 2D experiments. Most of the cross peaks in the proton-carbon correlation map were identified by the combined use of HMQC, HMQC-RELAY and HMQC-NOESY spectra, using already published proton chemical shifts. However, double-DEPT and triple-quantum experiments had to be performed for the edition of CH and CH2 side-chain groups, respectively, which were hardly visible on HMQC-type maps. The triple-quantum pulse sequence was adapted from its original scheme to be applicable to a natural abundance sample. The correlation between carbon chemical shifts and the apo-neocarzinostatin structure is discussed. In particular, 13C alpha secondary shifts correlate well with the backbone conformation. These shifts also yield information about the main-chain flexibility of the protein. Assignments reported herein will be used further for interpretation of carbon relaxation times in a study of the internal dynamics of apo-neocarzinostatin.

Amino Acid Sequence↗

PubMed1994

Anatomical basis of a fascio-cutaneous pedicle flap based on the infero-lateral collateral artery of the leg.

An anatomical study of 30 cases has been performed on the vascularisation of the distal third of the antero-lateral compartment of the leg, with particular reference to the relations of the infero-lateral collateral artery of the anterior tibial artery, the perforating branch of the peroneal artery, and the antero-lateral malleolar artery. A fascio-cutaneous pedicle flap based on the infero-lateral collateral artery is described noting that the superior, anterior, and posterior limits are similar to those of the lateral supramalleolar flap of Masquelet. The inferior limit of this new flap is 15 mm distal to the site of emergence of the perforating branch of the peroneal artery. The advantages of this flap are; a large surface area for cover, antegrade vascularisation, and no significant vascular sacrifice. The distal half of the calf can be covered both medially and posteriorly as well as the proximal half of the dorsum of the foot, the medial and lateral arch areas, the perimalleolar region, and the region behind the Achilles tendon. The flap requires the presence of the infero-lateral collateral artery of the tibialis anterior which can be confirmed either peroperatively or preoperatively by angiography.

Collateral Circulation↗

PubMed1994

[Flaps for covering extensive losses of cutaneous substance on the upper limb. Apropos of 15 cases].

The authors report on their recent experience concerning flap treatment of upper limb complex trauma, based on 15 cases. Proper wound care, and the use of healthy, well vascularised tissues for coverage is of paramount importance for good results, whose quality mostly depends on the severity of initial lesions. The results of this series are encouraging and appear to be a consequence of the great possibilities offered by the cutaneous or muscular flaps used.

Adult↗