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Biomedical subjects

J W Aston

Publications and source records attributed to J W Aston.

10 recordsLinked to original sources
PubMed1993

A comparison of paraplegic gait performance using two types of reciprocating gait orthoses.

This study examined the energy cost of ambulation using the reciprocating gait orthosis (RGO) and the modified Isocentric RGO in paraplegic spinal cord injured subjects. In 4 subjects, the rates of O2 consumption per minute, O2 cost per metre, heart rate (HR), respiratory exchange ratio, velocity, and physiologic cost index (PCI) were measured during ambulation with the two orthotic devices. PCI was calculated by dividing the difference between walking and resting HR by velocity. PCI was significantly lower during ambulation trials with the Isocentric RGO compared to the RGO, but was the only measurement that detected a significant difference between the two orthotic devices. These results indicate that energy costs of ambulation at self-selected speeds were lower with the Isocentric RGO compared to the standard RGO. Furthermore, PCI could be used as a sensitive indicator of gait efficiency in spinal cord injury subjects.

Adult↗
PubMed1992

Post-polio syndrome. An emerging threat to polio survivors.

The manifestations of post-polio syndrome typically occur 20 to 40 years after an acute episode of poliomyelitis and are confined to previously affected muscles. Because of motor unit remodeling and direct mechanical damage, weakness increases in individual muscles until it exceeds their narrow margin of reserve and becomes clinically apparent. Although the exact cause is not clear, generalized weakness often occurs when several muscles are affected and various postural limb strategies used by the patient are no longer able to compensate for the loss of muscle strength. The mainstays of treatment are life-style changes to avoid overexertion and use of light-weight orthoses and assistive aids to unload the extremities. Exercise and surgery have a limited role in management.

Electromyography↗
PubMed1992

A new canine cruciate ligament formed through distraction histogenesis. Report of a pilot study.

A modified Ilizarov external fixator was used to transfix the stifle joint in 13 dogs. A 1-cm cortical cancellous bone plug was outlined in the intracondylar notch of the femur after excising the anterior (cranial) cruciate ligament (ACL). Hardware attached to the plug allowed controlled distraction of the plug into a cut tibial channel trailing the regenerate ligament. No attempt was made to exactly recreate the normal anatomic course of the ACL. Some bone plugs became dislodged from the femur before distraction began, while others consolidated prematurely. These specimens produced scar only and served as a control group against which the regenerate ligament and normal ACLs were contrasted biomechanically, biochemically, and histologically. The dogs were killed at intervals from four to 21 weeks postoperatively. Load to failure at 21 weeks reached 71% of the mean normal. Histologic examination showed an improved fiber organization of the regenerate compared with the scar group. The regenerate and scar groups showed increased percent water compared with normal, while there was no significant difference in percent collagen and glycosaminoglycan content.

Animals↗
PubMed1990

Pediatric update #16. The orthopaedic presentation of neuroblastoma.

Twenty of 109 children (age, one day to 14 years) with neuroblastoma studied over an eight-year period initially presented with orthopaedic complaints. Patients were grouped into four categories: hip pain, a nonspecific limp, limb weakness, or back pain. The largest group involved the hip, and their conditions were most often misdiagnosed as suppurative arthritis. The initial hemoglobin level was the most consistent laboratory finding that suggested malignancy. This anemia was contrasted to that found in 74 children diagnosed with septic arthritis of the hip that presented during the same period. The anemia in the children with neuroblastoma was much more pronounced; in retrospect, it could have suggested a malignant process early in the evaluation.

Adolescent↗
PubMed1989

Physeal growth arrest of the distal radius treated by the Ilizarov technique. Report of a case.

Growth arrest of the distal radius may follow a severe injury to the growth plate. When the growth of the distal radius ceases in the child, continuing ulnar growth results in radial deviation of the hand and dislocation of the distal radioulnar joint. Treatment options in such a limb-length discrepancy are resection of the physeal bony bridge, lengthening of the shaft of the radius with bone graft using the principle of the Wagner technique, resection or epiphysiodesis of the distal ulna, and lengthening through a metaphyseal corticotomy without the use of bone graft. We report a case of metaphyseal lengthening of the radius employing the Ilizarov external fixator for controlled distraction osteogenesis.

Bone Diseases, Developmental↗
PubMed1979

In-toeing gait in children.

Torsional deformities in the lower extremities, resulting from constrained intrauterine position, tend to spontaneously correct toward the adult configuration during growth. Internal tibial torsion, metatarsus adductus and femoral anteversion are clinically evident conditions that occur because of arrested normal postnatal development. An understanding of the dynamics of spontaneous correction permits assessment of the child with in-toeing gait as well as the selection of proper treatment.

Adult↗
PubMed1977

Computer processing of fatty acid analysis data.

A Fortran computer program for the processing of fatty acid data from the anlysis of fats and oils by gas-liquid chromatography is described. The analytical method and calculations are described primarily for the analysis of butterfat and margaine fat, but with minor changes could be adapted to suit other fats and oils. The program computes the concentration of each fatty acid as weight % and mole %, the percentage glycerol, the theoretical iodine value, and other relevant combinations of fatty acids.

Chemical Phenomena↗