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Biomedical subjects

M Duhaime

Publications and source records attributed to M Duhaime.

At least 19 recordsLinked to original sources
PubMed2001

Lower limb muscle power relationships in bilateral able-bodied gait.

OBJECTIVE: The purpose of this study was to test the hypothesis that limb propulsion is mainly associated with the interaction of a number of muscle power bursts developed throughout the stance phase and that the control actions are mainly achieved by the contralateral limb through different power-burst interactions. We also hypothesized that the power activities of the propulsion limb would be related to those of the control limb. DESIGN: Sixty gait trials of 20 subjects with dominant right hands and right legs were chosen for analysis. Each trial represents a performance of an able-bodied gait. Data were assessed using an eight-camera, high-speed, video-based system synchronized to two force plates. The muscle powers and their related mechanical energies were calculated at each joint and in each plane of the lower limbs by use of an inverse dynamic technique. The Pearson correlation method was used to determine the relationships within each limb by use of the data identified by principal component analysis, whereas a canonical correlation analysis was performed to illustrate the interaction between the limbs. RESULTS: Gait propulsion was an activity initiated by the hip shortly after heel-strike and maintained throughout the stance phase. Control was the main task of the left limb as evidenced by the power absorption bursts at the hip and knee. The left limb power generations were generally secondary to control activities and were possibly involved in adjustments to correct the other limb's propulsion. Interlimb interaction further emphasized the functional relationship between forward progression and control tasks developed by each limb and highlighted the importance of the frontal and transverse plane actions during gait. CONCLUSION: These results do not support the hypothesis that the ankle was a major contributor to forward progression.

Adult↗
PubMed2000

The PDZ-interacting domain of cystic fibrosis transmembrane conductance regulator is required for functional expression in the apical plasma membrane.

Polarization of cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated chloride channel to the apical plasma membrane in epithelial cells is critical for vectorial chloride transport. Previously, we reported that the C terminus of CFTR constitutes a PDZ-interacting domain that is required for CFTR polarization to the apical plasma membrane and interaction with the PDZ domain-containing protein EBP50 (NHERF). PDZ-interacting domains are typically composed of the C-terminal three to five amino acids, which in CFTR are QDTRL. Our goal was to identify the key amino acid(s) in the PDZ-interacting domain of CFTR with regard to its apical polarization, interaction with EBP50, and ability to mediate transepithelial chloride secretion. Point substitution of the C-terminal leucine (Leu at position 0) with alanine abrogated apical polarization of CFTR, interaction between CFTR and EBP50, efficient expression of CFTR in the apical membrane, and chloride secretion. Point substitution of the threonine (Thr at position -2) with alanine or valine had no effect on the apical polarization of CFTR, but reduced interaction between CFTR and EBP50, efficient expression of CFTR in the apical membrane as well as chloride secretion. By contrast, individual point substitution of the other C-terminal amino acids (Gln at position -4, Asp at position -3 and Arg at position -1) with alanine had no effect on measured parameters. We conclude that the PDZ-interacting domain, in particular the leucine (position 0) and threonine (position -2) residues, are required for the efficient, polarized expression of CFTR in the apical plasma membrane, interaction of CFTR with EBP50, and for the ability of CFTR to mediate chloride secretion. Mutations that delete the C terminus of CFTR may cause cystic fibrosis because CFTR is not polarized, complexed with EBP50, or efficiently expressed in the apical membrane of epithelial cells.

Animals↗
PubMed1998

Complications of limb-lengthening in children who have an underlying bone disorder.

We retrospectively reviewed the results, particularly with regard to complications, of lengthening of long bones in eight children (nine limb segments) who had a limb-length discrepancy secondary to an underlying bone disorder (Group 1). The mean age of these patients was twelve years (range, six to sixteen years), the mean preoperative limb-length discrepancy was 6.0 centimeters (range, 2.7 to 8.8 centimeters), and the mean lengthening of the nine limb segments was 6.2 centimeters (range, 2.7 to 9.0 centimeters). Only two extremities were equalized. We compared the results in Group 1 with those of limb-lengthening in seven children (nine limb segments) who had a discrepancy secondary to post-traumatic growth arrest (Group 2) and seven children (seven limb segments) who had a discrepancy secondary to growth arrest following an infection in the bone (Group 3). All of the procedures were performed at our institution during the same time-period by the same surgeons. There were forty-one complications (twenty-five minor and sixteen major), with a mean of five complications per limb segment, in Group 1; twenty-six complications (twenty minor and six major), with a mean of three complications per limb segment, in Group 2; and twenty-two complications (fourteen minor and eight major), with a mean of three complications per limb segment, in Group 3. The results in Group 1 suggest that the Ilizarov technique for lengthening, although effective in restoring the length of the extremity, is associated with a higher rate of complications in patients who have a discrepancy due to an underlying bone disorder than in those who have a discrepancy due to growth arrest. Therefore, caution should be exercised before a lengthening procedure is recommended for a patient who has an underlying bone disorder.

Adolescent↗
PubMed1997

Management of fibular hemimelia: amputation or limb lengthening.

We reviewed retrospectively 22 patients (23 limb segments) with fibular hemimelia treated by amputation or limb lengthening to evaluate these methods of treatment. There were 12 boys and 10 girls, all with associated anomalies in the lower limbs. Twelve patients (13 limb segments) had early amputation and prosthetic fitting and ten had tibial lengthening using the Ilizarov technique. At the latest follow-up, the twelve patients who had amputation were functioning well and had few complications. The ten patients who had lengthening had suffered numerous complications, and all had needed either further corrective surgery or to wear braces or shoe-raises. Two of the ten lengthened limbs required late amputation for poor function or cosmesis. There were fewer hospital admissions, clinic visits, and periods of absence from school in the amputation group. Our findings suggest that amputation is a more effective method of management than limb-lengthening in severe fibular hemimelia. The Ilizarov method is an attractive alternative for selected patients, but its exact role is not yet established. One problem is that families often have unrealistic expectations of the surgical and prosthetic technology available and may refuse amputation when this has been recommended.

Amputation, Surgical↗
PubMed1996

Internal work estimation in three-dimensional gait analysis.

Many studies concerning the internal work of human motion have used two-dimensional kinematic models to estimate kinetic energy of the segments. The generalised co-ordinate concept has been applied here to a simultaneous and bilateral gait analysis. A three-dimensional kinematic model based on quaternions has been developed. To estimate the kinetic energy of a multi-body system, only two constants and two variables are needed: the segment body mass, the inertia tensor, the position and the orientation of the local co-ordinate system with respect to the inertial co-ordinate system. The variation of the kinetic energy is used in the calculation of the internal work for an able-bodies subject during the gait cycle. Both the internal work and the instantaneous energy correlation coefficient enable the determination of a conservative phase delimited by the beginning of the single support phase until the flat-foot phase, and a non-conservative phase corresponding to the period from heel-off to contralateral heel-strike including the double support phase.

Adult↗
PubMed1996

[Dorso-lumbal pain and idiopathic scoliosis in adolescence].

Current knowledge on the association between back pain and idiopathic scoliosis is often contradictory. The presence, localisation and importance of pain was evaluated for a cohort of 426 adolescents with AIS. Patients were recruited from a scoliosis clinic in a pediatric hospital. A questionnaire and an analogue visual scale graduated from 0 (no pain) to 100 (maximal pain) were used in order to verify more precisely, the importance of the association between AIS and back pain. Chisquare, linear regression and Student T-test were used for statistical analysis. 239 patients with right thoracic and left lumbar curves (RTLL) had a prevalence of pain of 54%. The mean of maximum pain intensity was 49 mm +/- 20. No relation was found between the severity of the scoliosis and back pain. The two groups (with and without pain) were comparable. Cobb angles were about the same for the thoracic and lumbar regions, as well as kyphosis and lordosis, weight, height and age. Risser sign, sex, brace and pelvic tilt were the only variables associated with pain (p < 0.0001). Association between AIS and pain is more frequent than generally reported. Pain appears to be more related with pelvic tilt than severity of the scoliosis.

Adolescent↗
PubMed1995

Modelling and gait evaluation of asymmetrical-keel foot prosthesis.

The paper documents a new concept in prosthetic foot design. It is based on the capacity of a flexible keel to allow a greater medio-lateral function than previously available. The heel has a complex curvature consisting of a medially concave shape that joins the mid-foot. There a hump acting as a leaf-spring ends at the metatarsal break, with an inwardly curved toe extremity. These curvatures contribute to increased medio-lateral control at heel-strike and propulsion for weight transfer and push-off. Results from finite-element modelling indicate that the asymmetrically shaped keel is at least twice as active in storing energy compared with a completely symmetrical one. A preliminary gait study is carried out for a 24-year-old below-knee amputee fitted with the new design, the SPACE foot and a dynamic elastic response foot with a symmetrical keel. With the SPACE foot, there is a 14% increase in walking speed combined with a reduction in the phasic asymmetries. The absolute difference between the initial and terminal double support is 1.4% for the asymmetrical keel design compared with 4.4% for the symmetrical keel foot prosthesis. The peak ankle power generation burst indicates that the SPACE foot behaves as a dynamic elastic response foot.

Biomechanical Phenomena↗
PubMed1995

Bilateral gait patterns in subjects fitted with a total hip prosthesis.

OBJECTIVES: The purpose of this report was to determine whether the muscle powers and the mechanical energies developed during the push-off period of the gait cycle of patients having a total hip prosthesis were different from able-bodied subjects as well as the effect on the nonoperated limb. DESIGN: Case control study. SETTING: All patients where independent and functional. PATIENTS: Four patients participated in the study. The indication for surgery was degenerative arthritis of the hip. There was also an able-bodied group. INTERVENTION: A Harris-Galante total hip prosthesis was used to restore hip stability and function. The patients were all operated on by the same orthopedic surgeon and had the same type of total hip replacement. MAIN OUTCOME MEASURE: Gait analyses showed that not only the hips of the surgical group were affected but also the knees. RESULTS: Peak power did not show any significant difference except for a decrease in the frontal plane of the operated hip power absorption. The operated hip developed 35% and 48% less energy than that of the able-bodied group in the sagittal and frontal planes, respectively. The nonoperated hip was also affected and developed 35% more energy in the sagittal plane than the operated limb but 20% less than that of the able-bodied group. There was a reduction of 47% in the energies developed in the knees of the surgical patient group. CONCLUSION: These results confirmed the presence of some mechanical dysfunction in the nonoperated limb.

Aged↗
PubMed1995

Natural history of muscle weakness in Friedreich's Ataxia and its relation to loss of ambulation.

From 1979 to 1992, 170 muscular assessments performed on 33 patients with Friedreich's Ataxia were reviewed. The average followup was 6 years. All muscle evaluations were done by the same team. It was possible to delineate a fairly regular and statistically significant pattern of slowly progressive and symmetrical loss of strength affecting mainly the lower limbs, and more specifically the pelvic girdle muscles. The first significant weakness was observed in the hip extensor group, followed in a variable fashion by other muscle groups of the lower limb. Upper limb and trunk muscles remained relatively spared until late in the disease process, with an overall strength approximately 80% of normal. Use of a wheelchair began at a mean age of 18.2 years, at which time the lower-limb strength averaged 70% of normal. Patients became totally unable to walk at a mean of age 20.5 years old, with a further decline in lower limb strength to 56% of normal. Weakness does not appear to be the primary cause for loss of ambulation in patients with Friedreich's ataxia.

Adolescent↗
PubMed1988

[Chondromyxoid fibroma: radiologic and radioisotope aspects].

Chondromyxoid fibroma is a relatively rare benign bone tumor whose histologic and radiologic patterns are well known. In this article, we describe a 16-year-old boy with such a tumor in his left tibia. Scintigraphically, this tumor is represented by a "doughnut sign". This aspect, though not pathognomonic, has been reported sporadically in a few diseases: osteoporosis circumscripta cranii, angioblastic meningioma, cranial coccidioidomycosis, and aseptic necrosis of frontal bone. Because of their sites, it is easy to reject these diagnoses in our patient. The most pertinent differential diagnosis with regard to the clinical, radiological, and scintigraphic aspects in the patient is that of a giant cell tumor.

Adolescent↗
PubMed1986

Natural history of scoliosis in Friedreich's ataxia.

Does scoliosis associated with Friedreich's ataxia behave like an idiopathic or a typical neuromuscular scoliosis? Should it be treated like an idiopathic or a neuromuscular curve? Since no precise information to answer these questions could be found in the orthopaedic literature, a retrospective study was undertaken of seventy-eight patients with Friedreich's ataxia who had been followed at our neuromuscular clinic. Fifty-six of these patients were found to have typical Friedreich's ataxia in accordance with the criteria of Geoffroy et al., and their cases were retained for analysis. Their mean age was twenty years (range, eight to thirty-three years). The average length of clinical follow-up was nine years and the average duration of radiographic follow-up of the scoliosis was 3.5 years. A scoliosis of more than 10 degrees was found in all patients and was associated with a hyperkyphosis in 66 per cent. Both sexes were equally affected. Fifty-seven per cent of the curves were double thoracic and lumbar; 14 per cent were thoracolumbar; 7 per cent, double thoracic and thoracolumbar; 7 per cent, thoracic; 4 per cent, lumbar; and 11 per cent, multiple small curves. Of the fifty-six patients whose cases were studied, thirty-six had been followed for at least ten years. Among these thirty-six, there were twenty whose curves were more than 60 degrees and progressed (Group I) and sixteen whose curves were 40 degrees or less and did not progress (Group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Evaluation of foot deformity using a three-dimensional geometric model.

A three-dimensional geometric model of the foot's bony structure based on the use of a stereoradiographic technique is presented. To illustrate the potential of such a model it has been applied here to the study of cavus foot in a patient having Friedreich's ataxia. This model permits an accurate evaluation of this complex spatial foot deformity.

Foot Deformities, Acquired↗
PubMed1984

Scoliosis assessment in Friedreich's ataxia by means of intrinsic parameters.

Spinal deformities have been evaluated in a five year retrospective study where 28 boys and 25 girls all having Friedreich's ataxia were on the average assessed once a year in a multidisciplinary clinic. Scoliosis seems somewhat more progressive in girls than in boys and more severe in non-ambulatory than ambulatory patients. Some of those scolioses are very progressive reaching 60 degrees to 100 degrees Cobb angle values requiring spinal surgery while other progress less rapidly and do well on their own. In addition it was shown that the intrinsic geometric spine curve parameters namely that of curvature and torsion are a powerful diagnostic tool in the assessment of evolutive scoliosis.

Adolescent↗