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Biomedical subjects

J Usabiaga

Publications and source records attributed to J Usabiaga.

15 recordsLinked to original sources
PubMed1999

Transient dissociation of bone metabolism induced by high performance exercise: a study in elite marathon runners.

Bone metabolism parameters were studied in 18 elite marathon runners (11 men and 7 women) who participated in the Marathon World Cup held at San Sebastian, Spain in 1993. Measurements were made before the race, immediately after the race, and 24 hours after the race. The most interesting finding was increased alkaline phosphatase (P < 0. 0001) and decreased tartrate-resistant acid phosphatase (P = 0.0035), which suggests that exercise produced uncoupling of the bone cell metabolism. Serum calcium corrected for proteins did not increase with exercise and at the end of the race there was a negative correlation between cortisol, which was significantly higher (P < 0. 0001), and corrected serum calcium (r = 0.53, P = 0.026) that was not present at baseline. Running time showed a significant negative correlation with baseline serum cortisol (r = -0.67, P = 0.0015) and a significant positive correlation with body mass index (r = 0.53, P = 0.0207). The increase in alkaline phosphatase persisted 24 hours after the race, which suggests that exercise produced an intense and sustained effect on osteogenic capacity.

Acid Phosphatase↗
PubMed1997

Adaptation of the lumbar spine to different positions in bicycle racing.

STUDY DESIGN: A radiologic and electromyographic study was done of the adaptation of the lumbar spine to high-performance cycling. OBJECTIVES: To evaluate changes in the lumbar spine produced by different cycling positions on different types of bicycles used during competition. METHODS: Three professional cyclists were observed to evaluate changes in the lumbar spine. Radiographs were obtained of the different positions adopted by the cyclists during competition, and changes in the angles of the lumbar spine were measured. An electromyographic study was done of the abdominal, lumbar, and thoracic paravertebral muscles. RESULTS: The cyclists' positions involved a change from discal lordosis to kyphosis. To obtain a more aerodynamic position, the cyclists flexed the hip and made the pelvis horizontal without changing disc angles. The contraction of paravertebral lumbar muscles was proportional to pedalling intensity and decreased in more aerodynamic positions. The tone of the paravertebral thoracic muscles depended on the extent of cervical hyperextension. Abdominal muscles remained relaxed in all bicycle positions and with all pedalling intensities. CONCLUSIONS: The changes observed could modify the normal biomechanics of the lumbar spine, but the overall mechanical load on the spine is reduced by shifting weight onto the upper limbs. The imbalance that occurs between the activity of flexor and extensor muscles could cause lumbar pain in persons without proper physical preparation.

Adaptation, Physiological↗
PubMed1995

Biochemical markers of nutrition in type-I and type-II osteoporosis.

We studied nutritional deficits, using as markers the levels of transferrin, retinol-binding protein, and prealbumin, in 20 women with osteoporotic hip fractures (type II), 40 women with vertebral fractures (type I), and two groups of age-matched control subjects. The concentrations of all three nutritional markers were lower in the two groups of patients than in their matched controls, and in type-I as compared with type-II osteoporosis. In the osteoporotic patients, simple linear regression showed a significant correlation between the variables which we studied (r2 ranged from 0.5 to 0.7; p < 0.001), the best correlation being between prealbumin and retinol-binding protein in type-II osteoporosis. Our results suggest that there is a more marked nutritional deficit in type-II than in type-I osteoporosis.

Aged↗
PubMed1995

Biochemical markers of nutrition in elite-marathon runners.

Although diet surveys have been made in marathon runners, as far as we know their nutritional state has not been evaluated by measurement of the so-called biological markers of nutrition, such as transferrin, retinol-binding protein, and prealbumin. We measured the levels of these substances in 18 marathon runners (11 men and 7 women; mean age 26.9 +/- 4.0 years) and in 22 controls (13 men and 9 women; mean age 26.2 +/- 3.6 years). As some of these markers are zinc-dependent, serum zinc levels also were measured. Likewise, serum calcium, phosphorus, and magnesium levels were measured to ascertain the athletes' mineral status. Calcium corrected for proteins, phosphorus, magnesium, and zinc did not differ between the marathon runners and controls; likewise, there were no differences in serum ferritin and glucose levels. As regards the biological markers of nutrition, prealbumin levels were higher in athletes than in controls (31.7 +/- 4.7 vs 28.9 +/- 4.8 mg/dl, p < 0.025). There were no differences in the levels of retinol-binding protein and transferrin between runners and controls.

Adult↗
PubMed1992

Clinical and ultrastructural analysis of failures in chemonucleolysis.

A series of 12 patients with failed chemonucleolysis were analyzed to determine the various causes of such failures. The ultrastructural findings observed in laminectomy specimens did not account for the failure in the enzyme treatment. The findings suggested deficient cellular nutrition secondary to enzymatic histolysis of the nucleus pulposus.

Chymopapain↗
PubMed1991

[Comparative study between conservative orthopedic therapy and intramedullary osteosynthesis of diaphyseal tibial fractures].

The authors present the results obtained in a series of 275 tibial shaft fractures, 216 of which were treated by a functional orthopaedic procedure and 59 with different kinds of nailing techniques. The results are evaluated according to the criteria established by Johner and Wruhs. "Good" results were obtained with both kinds of treatment; "excellent" results were slightly more frequent with nailing techniques, owing to better alignment and a lesser degree of shortening in the fractures, although the residual deformities after the functional orthopaedic treatment were tolerable.

Adolescent↗
PubMed1989

[Reconstructive surgery using a massive prosthesis in loosening of a hip prosthesis].

Thirteen cases with loosening of THR treated by a massive prosthesis are reviewed. In previous years, with more conservative surgery, the loss of bone stock was most important. The results after a long follow-up were satisfactory. This was a desperate procedure during a period without a bone-bank. Despite the major problems with failure of this procedure, the author still recommends it in elderly patients who need early mobilization or when the use of a bank-bone is not possible.

Adult↗
PubMed1989

An experimental study of the redistribution of patellofemoral pressures by the anterior displacement of the anterior tuberosity of the tibia.

Using a series of miniature piezoelectric transducers constructed by the authors, a study was made of the effect of anterior displacement of the tuberosity of the tibia on the distribution of pressures in the patellofemoral joint. Proportionally, the most efficient displacements are those set at 1 cm; after this, and as advancement of the tuberosity is increased, the overall pressure continues to decrease progressively (although more slowly) because there are zones that, according to their situation, receive increased instead of decreased pressures. Consequently, values even higher than those of the original situation are reached. This is the case of the proximal part of the patella, particularly on its lateral facet. This situation can affect the results in cases where the lesion is preferentially located on the proximal part. In these cases it may be enough to advance 1 cm with which overall decompressions close to 50% of the pressure that initially affected the patellofemoral joint are obtained. In very evolved cases or when the lesions are located centrally or distally, it may be worthwhile to advance maximally in spite of the possible complications, seeking the greatest decompression effect that intense advancements can achieve.

Biomechanical Phenomena↗
PubMed1988

Sternoclavicular dislocation. Treatment and complications.

Based on Allman's classification, the authors conducted a critical study on the results of treatment of 17 sternoclavicular dislocations, 14 anterior and 3 posterior. They propose conservative treatment for subluxations and operative treatment for total dislocations, particularly when posterior. Tomography was required for precise diagnosis. The advantages of open reduction are stressed and the complication of intra-thoracic migration of crossed Kirschner wires used to stabilise reduction and capsular suturing is described.

Adolescent↗
PubMedDate not supplied

Congenital brachymetatarsia: three cases.

We report on three cases with congenital brachymetatarsia, one with bilateral affectation, together with the results of a lengthening of the short metatarsal bones by progressive axial distraction using an external minifixator. The method proved to be easy to implement, permitting immediate functionality of the ankle and early load bearing. The immediate results (cosmetic) and later findings (functional) were excellent in all three cases.

Adolescent↗
PubMedDate not supplied

Post-chemonucleolysis computed tomographic findings.

The CT findings observed 6 months and 2 years after chemonucleolysis in 50 and 34 patients are reported. Emphasis is placed on the persistence of the hernia image in nearly 70% of the cases, together with an increase in degenerative intradiscal signs and degeneration of the facet joints; however, this did not lead to poor results 2 years after chemonucleolysis.

Adolescent↗