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Biomedical subjects

R Louis

Publications and source records attributed to R Louis.

At least 19 recordsLinked to original sources
PubMed1992

LY 186655, a phosphodiesterase inhibitor, inhibits histamine release from human basophils, lung and skin fragments.

LY 186655 (Tibenelast, Lilly) is a new phosphodiesterase inhibitor, not derived from the xanthine, possessing bronchodilating activity in animals. The aim of this work was to study the effect of LY 186655 and theophylline on histamine release from human leukocytes, skin and lung fragments. Histamine was measured using a spectrofluorometric method. Both drugs (3 x 10(-5)-3 x 10(-3) M) exhibited a dose-dependent inhibition on anti-IgE (1/2000)-induced histamine release from human leukocytes. At 3 x 10(-3) M, theophylline was significantly more effective than LY 186655 (mean inhibition 94 and 42%, respectively). On lung fragments, theophylline and LY 186655 (3 x 10(-5)-3 x 10(-3) M) caused strong and comparable inhibitory effects on anti-IgE (1/500)-induced histamine release with a mean inhibition reaching maximally 65%. Histamine release induced by compound 48/80 (1 mg/ml) on sliced human foreskin was reduced with both drugs (3 x 10(-3) M) by about 37%. We conclude that LY 186655 inhibits in vitro immunological histamine release from human lung and cutaneous mast cells as well as basophils with a similar pattern of activity to theophylline.

Adult↗
PubMed1988

Anatomic basis for implantation of the Ilizarov system in the leg.

Ilizarov's method of implanting an external circular fixator requires the placement of at least 8 transfixion pins. The neurovascular hazards and the need to leave the posterior and lateral compartments free motivated this study, based on serial radiographic sections after injection of the entire arterial system. Two reference pin-planes were determined, 1 posterolateral and 1 lateromedial. The sites of insertion of the pins rely on classical radiographs of the bones of the leg. The addition of beaded pins must be made on a realigned and stabilized limb. The imprecision of aim due to the bone structure and the shape of the pin leads to the definition of forbidden zones where any transfixion is dangerous. The concept of a neurovascular pyramid with its base at the distal metaphysis and of a periosseous tendinous circlet at that level implies a search for a compromise between the stability of the assembly and the dangers of the method.

Bone Nails↗
PubMed1988

[Pars interarticularis reconstruction of spondylolysis using plates and screws with grafting without arthrodesis. Apropos of 78 cases].

Between 1978 and 1985, 78 reconstructions of the pars interarticularis were performed for painful spondylolysis in which there had been failure to respond to conservative methods and the subjacent disc was not degenerate. Sixty-five patients were reviewed with a follow-up greater than 2 years and a mean of 4.4 years. The concept of pars interarticularis reconstruction can be attributed to Kimura (1968), Buck (1970) and Nicol and Scott (1986). It consists of a posterior approach with freshening of the margins of the defect, the insertion of cancellous chips taken from the spinous processes, resection of the tips of the articular processes above the partes interarticulares and fixation with a butterfly plate and screws which was devised for this purpose. The plate was removed after 6 months. The rate of union after this procedure was 93.5 per cent and rose to 95.7 per cent after a secondary bone graft. Two bilateral non-unions required a lumbosacral arthrodesis. The results were excellent or good as regards pain in 86 per cent of cases. A return to heavy work and intensive sporting activity was possible in 88 per cent of cases. Movement of the lumbosacral spine was reduced by a mean of 41 per cent.

Adolescent↗
PubMed1987

Anatomic factors in the femoral implantation of the Ilizarov external fixator.

Ilizarov's method of external fixation with compression or distraction for lesions of the limbs demonstrates new possibilities in osteogenesis. Its performance with double horizontal pinning on several external rings calls for precautions to avoid lesions of the vessels, nerves and joints. This study, based on anatomic sections radiographed after opacification of the arterial system, makes it possible to propose rules for insertion of the pins. Insertion of the anteromedial pins of the thigh should be made 2 cm in front of the line of projection of the femoral artery, between the middle of the inguinal ligament and the posterior margin of the medial condyle. Insertion of the posterolateral thigh pins should be made 2 cm lateral to the line of projection of the sciatic nerve, between the center of the ischiotrochanteric interval, the apex of the popliteal fossa and the posterior aspect of the head of the fibula.

Bone Nails↗
PubMed1987

[Ventral approach to the cervical spine].

Since they were introduced in 1950, ventral approaches for surgical operations on the cervical spine have become widely used. The most frequently used is the anteromedian approach, passing along the anterior border of the sternocleidomastoideus muscle and then between the upper gastrointestinal tract and the vascular bundle to give access to the spine. This approach allows access to practically every segment of the cervical spine. The significance of the transoral approach is stressed in the literature, and we ourselves are also convinced of its importance. In this paper, however, the combined anteroposterior procedures and the cervicothoracic methods used for the transitional zone are also described. Complications affecting the upper gastrointestinal tract, the vessels or the nerves are always possible, and to reduce their likelihood to a minimum it is essential to make a detailed study of the complicated anatomy of the neck region.

Cervical Vertebrae↗
PubMed1986

Fusion of the lumbar and sacral spine by internal fixation with screw plates.

From 1972 to 1982, 455 patients had arthrodesis and other operations with screw-plate internal fixation of the lumbosacral spine. Of these 455 patients, 440-413 of whom had had spinal fusion and 27 of whom had undergone pars interarticularis reconstruction--were evaluated for a mean follow-up period of 31.6 months. The principal indications for single-stage posterior fusion, which was performed in 266 cases, were severe degenerative joint disease and painful spondylolysis, while the primary indications for combined anterior and posterior repair, which was undertaken in 145 cases, were spondylolisthesis and malignant tumors. Two cases had single-stage anterior fusion. Initial anterior surgery was performed to achieve reduction of vertebral displacement, while the posterior approach was carried out to allow for fusion of the posterior joints and for osteosynthesis; specially-designed screw plates were attached to the pedicle for this purpose. The rate of solid fusion was 97.4% in the single-stage posterior procedures and 100% in patients who had been treated by a combined approach. Only five neurologic complications were encountered out of the combined approach (two regressive cauda equina syndromes and three regressive L5 nerve root pareses), and these occurred early in the investigation, when the technique was still being refined. Only six cases of single-stage posterior approach sustained a monoradicular lesion that subsided after the offending bone screw was removed. Such complications can be avoided if the surgeon is thoroughly familiar with the techniques described.

Adolescent↗
PubMed1985

Spinal stability as defined by the three-column spine concept.

The three-column spine concept is supported by anatomical data from dry European and African skeketons, by experiments on fresh cadaver spines without chemical fixation and by an extensive clinical and surgical experience. There exists an axial and a transverse stability. Axial stability is maintained along a vertical column system: this consists of two columns at the C1-C2 level and three columns from C2 to the sacrum. The anterior column is formed by the vertebral bodies and discs, and the two posterior columns by posterior joints. Transverse stability at the motion segment levels is produced by a coupling of bony buttresses and ligamentous brakes. The three-joint motion segment is characterized by a triangular disposition of joints with opposing joint spaces, thus supporting the articular orthogonal triangulation concept. These observations have a clinical relevance in the field of spinal growth, changes consequent upon wear in spinal joints and clinical instability.

Humans↗
PubMed1979

[Polyarteritis nodosa with ureteric stenosis. Two cases (author's transl)].

In two cases, surgical exploration fully confirmed that ureteric stenosis was related to PAN. There are four cases of this association in the litterature but it is probable that the frequency of such stenosis is underestimated: amongst 75 patients being treated for PAN in our department, only 11 underwent intravenous urography, 10 being abnormal.

Adult↗
PubMed1979

[Cervical spine. II. Fractures and dislocations (author's transl)].

Clinical and radiologic investigations in spinal fractures and dislocations must allow assessment of modifications in osteoarticular and neural functions. With respect to osteoarticular function it is necessary to identify the presence of both temporary or permanent instability and impaired static equilibrium. Regarding neural functions we must not only evaluate the neurologic damage but also residual stenosis of the spinal canal and sometimes of the intervertebral foramina. Compression induced by such stenosis is best demonstrated on métrizanide myelography. Management is currently aimed at better and more rapid correction of morphologic damages and disturbed stability. These goals are achieved by reduction and stabilisation using orthopedic or surgical techniques, the later involving an anterior or posterior approach to osteosynthesis. Systematic suppression of factors causing neural compression has led to a greater recovery rate than in the past.

Cervical Vertebrae↗