Biomedical subjects

J Chouteau

Publications and source records attributed to J Chouteau.

At least 19 recordsLinked to original sources

PubMed2006

[Accuracy of total knee replacement bone cuts using a conventional ancillary system: 300 Innex total knee arthroplasties].

PURPOSE OF THE STUDY: Short-term functional results and long-term outcome in terms of stability and wear greatly depend on the precision of the bone cuts. We wanted to know whether conventional ancillaries are still competitive in terms of accuracy in comparison with computer-assisted navigation systems. A few comparative studies favor navigation, but have generally only included a small number of patients. We studied radiographically a prospective consecutive series of 300 total knee prostheses (Innex, Zimmer) implanted with the conventional technique by the same operator. MATERIAL AND METHODS: A telegonometric view in the upright position and a short lateral view were obtained in all patients. In the AP view, implants were measured in comparison with the mechanical axis of the femur (F) and the tibia (T). On the lateral view, the prosthesis-tibial shaft angle (PT) was measured from the proximal portion of the tibial shaft and the prosthesis-femoral shaft angle (PF) from the distal portion of the femur. The same operator made all measurements using the same optimal conditions. The series included 178 women and 122 men, mean age 72 +/- 8 years who presented genu varum (n = 248 knees) and genu valgum (n = 52 knees): degenerative disease (n = 238), polyarthritis (n = 4), hemophilic arthropathy (n = 3), necrosis (n = 3), revision of unicompartmental prosthesis (n = 8), and osteotomy (n = 44). RESULTS: The standard x-ray protocol was performed at two months in all patients. The mechanical axis (HKA) was 179.4 +/- 2.4 degrees (range 173-186 degrees) and was +/- 3 degrees in 87% of knees with no difference for varum and valgum. F was 90.1 +/- 1.4 degrees (87-95), with +/- 3 degrees for 98.7%. T was 89.3 +/- 1.5 degrees (85-94) with +/- 3 degrees for 95.6%. PF was 88.6 +/- 1.6 degrees (84-93) for 87%, PT was 87 +/- 2 degrees (81-93) with +/- 3 degrees for 94%. The four cuts were within +/- 3 degrees for 227 prostheses (77%), within +/- 2 degrees for 156 (52%) and within +/- 1 degrees for 56 (18%). Measurements made again one year after implantation for 203 knees gave the same results. Operative time for implantation was 68 +/- 23 minutes for implantation and 85 +/- 23 minutes including complete closure (less than 60 minutes for 68 knees). DISCUSSION: The accuracy of each cut was satisfactory on average with a small standard deviation. Recent data in the literature show that the accuracy in our series is comparable with that obtained currently with navigation systems. In light of this experience, it can be seen that better precision can be achieved for each of the cuts. CONCLUSION: The accuracy of conventional instrumentation systems is still comparable with that obtained with computer-assisted surgery. The purpose of this study was not to question the benefit of navigation, but to establish a basis upon which progress can be measured. The results enabled a more realistic comparison of the precision of navigation systems and also can be comforting for operators still using conventional ancillaries.

Adult↗

PubMed2006

[One-stage reconstruction of the two cruciate ligaments with a single autogenous graft from the extensor system: techniques and results of 25 chronic cases].

PURPOSE OF THE STUDY: Chronic tears of both cruciate ligaments are rarely encountered. Management practices have varied. One-stage reconstruction of both ligaments using arthroscopically implanted allografts was proposed starting in 1996 for such chronic laxity but only 44 cases have been reported in six papers mixed in with recent cases raising very different problems. Treatments using allografts or autogenous grafts or both implanted arthroscopically have often been combined with open surgery. We report a retrospective analysis of 25 knees treated with the same technique from 1983 to 2004: reconstruction with a single transplant taken from the extensor system. MATERIAL AND METHODS: A 30-cm lenght patella tendon-patella-quadriceps tendon graft was harvested. The patellar block was fixed in a hole drilled under the tibial spine, the patellar tendon replacing the posterior cruciate ligament and the quadriceps tendon passing through the lateral condyle and replacing the anterior cruciate ligament before implantation on Gerdy's tubercle, this also creating an extra-articular plasty with the same implant. Medial, lateral and posterior plasties were performed, depending on the radiographic assessment of laxity. Twenty-five knees with major laxity and instability were operated on, including 14 in two-stage operations. The differential anterior drawer was 10+/-3 mm medially and 9+/-5 mm laterally. The posterior drawer at 70 degrees was 15+/-4 mm medially and 10+/-6 degrees laterally. The total anteroposterior laxity of the medial compartment was 29 mm, it was 30 mm for the lateral compartment. Lateral laxity was considered major (>10 degrees ) in 17 knees and medial laxity in 7. Lateral and medial laxities were associated in eleven knees. Hyper-extension was very severe in five knees. RESULTS: Functional outcome at mean 6.5 years follow-up (range 1-21) was satisfactory (except in three knees) allowing renewed occupational activity. Resumption of sports activity was less marked and none of the knees was in IKDC class A, corroborating results in the literature. Anatomic outcome was assessed on the radiological drawer decrease which was modest, mean gain in the anterior drawer measuring 4 and 5 mm in the medial and lateral compartments and mean gain in the posterior drawer measuring 5 mm medially and 3 mm laterally. Peripheral laxity was corrected for best. DISCUSSION: Classically, one or other of the cruciate ligaments is repaired, sometimes both, but in a two-stage procedure associating two different methods and autogenous tendon grafts. One-stage reconstruction of both cruciate ligaments with a single autogenous graft and a wide approach has not led to any complications. One-stage reconstruction using this technique has several advantages: one anterior incision, single transplant which also enables lateral plasty, short immobilization time with rapid rehabilitation.

Adolescent↗

PubMed2005

Is the CAG repeat of mitochondrial DNA polymerase gamma (POLG) associated with male infertility? A multi-centre French study.

BACKGROUND: Recent data emphasized the implication of polymerase gamma (POLG) CAG repeats in infertility, making it a very attractive gene for study. A comparison of POLG CAG repeats in infertile and fertile men showed a clear association between the absence of the usual 10-CAG allele and male infertility, excluding azoospermia. It has also been suggested that the POLG gene polymorphism should be considered as a possible contributing factor in unexplained couple infertility where semen parameters are normal. In this study, we investigated the POLG CAG repeats, in a well-defined population of patients with severe male factor infertility. METHODS: We conducted a large study of POLG CAG repeats in 433 infertile and 91 fertile, normozoospermic and healthy males. In all subjects, phenotypic data, including semen parameters, hormonal status and clinical profiles, were available. RESULTS: Thirteen 'homozygous mutants' (3%) were found among the 433 idiopathic infertile patients. The follow-up of the 13 'homozygous mutant' resulted in pregnancy for more than half of the couples, through assisted reproductive techniques or even spontaneously. In addition, one 'homozygous mutant' was identified in 91 fertile men (1.1%) CONCLUSION: Under our conditions, our study does not confirm any relationship between the polymorphic CAG repeat in the POLG gene and male infertility.

Adult↗

PubMed2005

[Not Available].

Explore the source record for details and available documents.

Journal Article↗

PubMed2003

Effect of micro- and macroporosity of bone substitutes on their mechanical properties and cellular response.

The control of porosity morphology and physico-chemical characteristics of calcium phosphate bone substitutes is a key-point to guaranty healing success. In this work, micro- and macroporosity of materials processed with 70% Hydroxyapatite (HAP) and 30% beta-tricalcium phosphate (beta-TCP) were controlled by sintering temperature and porogen addition, respectively. Porosity was quantified by scanning electron microscopy (pore size) and mercury intrusion porosimetry (interconnection between pores). The content of macrointerconnections and their size were dependent on porogen content, shape, and size. Mechanical properties (compressive strength) were strongly dependent on macroporosity size and content, on the basis of exponential laws, whereas microporosity ratio was less influent. Relying on those results, three types of materials with contrasting porous morphologies were processed and assessed in vitro, in primary culture of human osteoblasts and fibroblasts. With both types of cells, an exponential cellular growth was effective. Cells colonized the surface of the materials, bridging macroporosity, before colonizing the depth of the materials. Cell migration across and into macroporosity occurred via the emission by the cells of long cytoplasmic extensions that hanged on microporosity. Both macroporosity and macrointerconnectivity size influenced the penetration of cells. An interconnection size of 15 microm appeared to be effective to support this invasion without bringing down mechanical strength.

Journal Article↗

PubMed2003

[Cellular culture of osteoblasts and fibroblasts on porous calcium-phosphate bone substitutes].

PURPOSE OF THE STUDY: Calcium phosphate ceramics are synthetic bone substitutes able to fill in bone destruction as a support of the bone growth. This work consisted in an in vitro assessment of osteoblasts and fibroblasts cultures on macroporous calcium-phosphate bone substitutes to analyze the interaction between cells and bone substitute. MATERIALS AND METHODS: The macroporous ceramic was composed of 70% hydroxyapatite and 30% tri-calcium phosphate with known mechanical and physico-chemical properties. Three compounds were processed with different size of macropore and with or without microporosity on their surface. Cells were seeded on discs measuring 10 mm in diameter and 2 mm in thickness. Cellular viability was evaluated by the MTT test for every stage of observation. An histological study to observe the invasion in the depth of discs was performed. Scanning electron microscopy was used to analyze the cellular comportment in contact with the surface of substitutes. RESULTS: An exponential cellular growth was effective on each substitute with the two cellular types. Cells spread on the surface of the compounds covering macropores and colonized the depth of the discs. A size of macropore of 300 microm or more seemed to support this invasion. 15 microm sized interconnections appeared to be effective to allow cell migration between macropores. The cell proliferation was similar on substitutes with or without microporosity. CONCLUSION: Biomaterials currently used as bone substitute are more or less osteoconductive but they have no osteoinductive property. A hybrid association of calcium-phosphate ceramic with osteogenic cells should promote the development of a calcium phosphate compound with osteoinductive capacity.

Biocompatible Materials↗

PubMed2001

In vitro fertilization and blastocyst transfer for carriers of chromosomal translocation.

Blastocyst transfers (BT), may benefit chromosomal translocation-carrier couples who suffer multiple miscarriages or are unable to achieve pregnancy following classical ART techniques. In vitro culture applies an additional selection pressure, so that those embryos which achieve blastocyst formation have higher survival probability as healthy balanced translocation carriers or unaffected embryos. Sixteen IVF cycles were performed in 11 patients. When blastocyst are obtained, implantation rate per blastocyst and delivery rates (7/11 cycles, eight healthy babies born) are high. However, the overall blastocyst formation rate is low (20%), and as a consequence in nearly half of the cycles, no blastocyst can be obtained. We propose that this strategy may be used initially as an alternative or a complement to preimplantation genetic diagnosis, and to apply the forces of natural selection in vitro.

Adult↗

PubMed1999

Birth weight and sex ratio after transfer at the blastocyst stage in humans.

OBJECTIVE: To analyze the birth weights and sex ratio of infants born after blastocyst transfer. DESIGN: Retrospective analysis. SETTING: Three infertility clinics. PATIENT(S): Patients admitted for IVF with blastocyst transfer. INTERVENTION: None. MAIN OUTCOME MEASURE(S): Birth weights and sex ratio of infants born after blastocyst transfer. RESULT(S): Statistically significantly more male infants were born after transfer of fresh blastocysts, either cocultured or cultured in sequential media. No specific differences in birth weight were observed between infants born after blastocyst transfer and those born after spontaneous conception. CONCLUSION(S): More male infants than female infants were born after blastocyst transfer when transfers were performed as soon as the blastocyst stage was reached and male embryos had a faster cleavage rate.

Birth Weight↗

PubMed1999

[Sequential media: why and how?].

Blastocyst transfer is highly recommended for the following indications to avoid repeated failure of implantation: related to maternal, paternal and cytogenetic aspects on the embryonic side and/or uterus motility. Sequential media have now replaced coculture in order to produce blastocysts. The basic idea of sequential media is to follow embryo's need. There are 2 phases during preimplantation period: the first one corresponds to a development through maternal stores, gathered during maturation, before genomic activation. This requires a complete protection against free radicals (through EDTA), and a decrease in the concentration of glucose and phosphate: mitocondrial function is impaired. Regulation of the endogenous pool is not perfect. Then at the time of genomic activation, there is an increased need for numerous metabolites. Insulin can be added as the I-Receptor appears at the 8-cell stage. The medium used during this phase has to be rich.

Coculture Techniques↗

PubMed1988

[Evolution from 1976 to 1986 of bacterial prevalence and sensitivity to urinary antibiotics of bacteria isolated from urine cultures at a city microbiology laboratory].

The evolution of the prevalence of the bacterial strains isolated from UTI cases (bacteriuria greater than or equal to 10(5)/ml has been studied over a 11 year-period from 1976 to 1986, in a clinical practice microbiological laboratory from a rural area. E. coli was the overall most frequently isolated species, followed by P. mirabilis (74.4% and 11.2% respectively), by the Klebsiella-Enterobacter group (4.8%), and staphylococci (represented by coagulase negative staphylococci) (4.9%). The relative frequency of the different species has been relatively stable year after year during the considered period. The evolution of the resistance to 4 antibiotics has been studied species by species and year after year for the Gram negative bacilli: a definite evolution towards resistance has been noted for ampicillin until 1985, followed by a decrease in 1986. The same tendency, although less pronounced, has been noted for cotrimoxazole. The frequency of the resistance to nalidixic acid has slightly increased from 1976 to 1986 (1.9% to 6.5%), as well as to pipemidic acid from (0% to 4%). The quinolones stand in 1987 as a good first line treatment of UTI in community, and especially in rural areas, and the role of the clinical practice microbiological laboratory for the epidemiological surveillance has to be stressed.

Ampicillin↗

PubMed1973