Search PubMed⌕ Search

Biomedical subjects

J Vidal

Publications and source records attributed to J Vidal.

At least 217 records · Page 12Linked to original sources
PubMed1988

Coupling redox and enzymic reactions improves the sensitivity of the ELISA-spot assay.

A method is described to increase the sensitivity of the conventional bromo-chloro-indolyl-phosphate ELISA-spot assay. The method is based on the addition of nitro blue tetrazolium to the substrate: the hydrogen ions released during the conversion of indoxyl to indigo, reduce the tetrazolium salt to insoluble diformazan. In this paper, the nitro blue tetrazolium assay is shown (a) to be more sensitive and faster than the bromo-chloro-indolyl-phosphate assay, and (b) to disclose precisely those areas where antibody secretion has occurred.

Alkaline Phosphatase↗
PubMed1988

In vivo phosphorylation of sorghum leaf phosphoenolpyruvate carboxylase.

The use of immunological techniques allowed us to purify close to homogeneity phosphoenolpyruvate carboxylase (PEPc, EC 4.1.1.31) from sorghum leaf. It was thus established that: 1) this protein is phosphorylated in vivo on seryl residues; 2) in C4-type photosynthesis, the phosphorylation process mainly concerns the PEPC isozyme form G; 3) enzyme phosphorylation displays significant variations through a day-night alternation which therefore suggests light control of the process.

Carboxy-Lyases↗
PubMed1988

Generation of anti-ssDNA antibodies by persistent immunization of mice with sheep erythrocytes.

Immunization of (DBA/2) mice with sheep erythrocytes (1 X 10(8) red cells, once weekly for 2 months) elicited anti-sheep erythrocyte antibodies, a part of which combined with ssDNA. By contrast, immunization with rat (Fisher) erythrocytes (1 X 10(8) red cells, once weekly for 2 weeks) did not elicit antibodies cross-reactive with ssDNA. The antibody response (IgM and IgG) to sheep erythrocytes rose sharply and subsequently tapered off (usually within the first 2 weeks). The level of IgG antibodies cross-reactive with ssDNA increased and, after ca. 1 month, decreased. No increase in anti-trinitrophenyl antibodies was detected. These results suggest the existence of a homeostatic mechanism. The anti-ssDNA antibodies bound to sheep erythrocytes, ssDNA and, marginally, to trinitrophenyl-gelatin; they did not bind to poly-D-glutamic acid, rat erythrocytes or mouse erythrocytes. Treatment of sheep red blood cells with neuraminidase, proteinase K, trypsin, or DNase did not alter the erythrocytes' capacity to bind the anti-ssDNA antibodies; solubilization of the erythrocytes with Triton X-100 abolished the binding. Neither a methanol:chloroform (1:1) extract (which contains the erythrocyte phospholipids) nor the residue (left after the extraction) bound anti-ssDNA antibodies. The determinant mediating the binding could be conformational.

Animals↗
PubMed1988

[Recurrences of supratentorial meningiomas. Apropos of 17 cases].

17 cases of recurrent meningiomas observed during a 10 years period are reviewed. Meningiomas with a second localisation different from the first were excluded from the study. The tumor recurrence occurred mostly during the first five years after the surgical procedure. One case with femoral and pulmonary metastasis is described. Several factors may play a role in the genesis of the recurrence: age, sex, the tumor localisation, CT scan, the importance of the tumor ablation, the histology. In almost all cases a radiotherapy was carried out after the second surgical procedure. This retrospective study suggests the need for multifactorial prospective analysis with clinical, paraclinical and fundamental factors. Such a study would be useful to precise the natural history of meningiomas.

Adult↗
PubMed1988

[Total hip arthroplasty in the presence of sepsis].

Sixty-seven cases of total arthroplasty of the hip in the presence of sepsis performed between 1974 and 1986 were reviewed. These prostheses were inserted in 57 cases to replace septic prostheses. Forty-six were infected total hip prostheses and 11 were infected head and neck replacement femoral prostheses. In 10 cases arthroplasty was performed for subacute septic arthritis, usually secondary to trauma. In seven cases, a simple revision of the prosthesis by excision and lavage of infected tissues was performed. In 51 cases, a total hip replacement arthroplasty was performed in one stage. When one of the components was not loose it was preserved; in 17 cases the femoral cement was retained and in six the acetabular cup was retained. In eight cases, the prosthesis was removed, excision of the tissues was made and a total hip arthroplasty inserted after a minimum interval of six months. As regards infection, success was achieved in 69 per cent of cases rising to 85 per cent after secondary removal of the prosthesis. In relation to function, a good or fair result was achieved in 72 per cent of cases. The results were favourable in 81 per cent of cases with complete exchange of prostheses and in 75 per cent with preservation of the femoral cement. Preservation of the acetabular cup was only successful in 40 per cent of cases. Accessory factors in the prognosis were the addition of a bone graft, which became incorporated in 29 cases out of 30 and the nature of the organism which was of no significance, except that staphylococcus epidermidis and Koch's bacillus proved to be more easy to treat.

Acetabulum↗
PubMed1988

[Combination of external fixator and internal synthesis in fractures and pseudoarthrosis of the leg. Principle indications and results].

A combination of internal and external fixation has been used on 58 occasions in fractures and pseudarthroses in the leg. In almost two-thirds of the cases, the fractures were compound. Several situations favour this combination of fixation: internal fixation complements an initial external fixation by stabilising the fracture site in the shaft or by allowing reconstruction of joint surfaces, external fixation complements any inadequate internal fixation due to comminution of the fracture or poor skin cover that only allows a minimum of internal fixation, external fixation secondarily comes to the help of internal fixation in cases of skin necrosis or secondary bone infection. The authors believe that a combination of internal and external fixation has real advantages and that, when used with good sense, it should not lead to any specific complications.

Adolescent↗
PubMed1987

Photoregulation process of sorghum leaf phosphoenolpyruvate carboxylase: study with monoclonal antibodies.

Monoclonal antibodies were produced against the G isozyme subunit of PEP carboxylase (PEPC) from Sorghum leaves by the hybridoma technique. More than 400 antibodies-producing hybridomas to PEPC were produced from the fusion of spleen cells from immunized mice with NS1 myeloma cells. By using an ELISA, three hybridomas (91-G, 83-G, 49-EG) were selected. Monoclonal antibodies were subsequently characterized in a Western experiment; Mabs 83-G and 91-G were found to be highly specific to the G isozyme whereas Mab 49-EG recognized both forms (E and G isozymes) of the enzyme. Addition of Mabs to the enzyme preparation did not modify its catalytic activity nor its activation by glycine. Use of these probes provided direct and definite evidence of the specific enhancing effect of light on the G form and on its corresponding mRNA.

Antibodies, Monoclonal↗
PubMed1987

Photocontrol of sorghum leaf phosphoenolpyruvate carboxylase : characterization of messenger RNA and of photoreceptor.

The mechanism underlying the light effect on phosphoenolpyruvate carboxylase (PEPC) from the C(4) plant sorghum (Sorghum vulgare Pers., var Tamaran) leaves was investigated. Following exposure to light a new isozyme of PEPC, specific for the green leaf and responsible for primary CO(2) fixation in photosynthesis, was established. Northern blot experiments revealed the presence of PEPC mRNA showing a molecular weight of 3.4 kilobases. During the greening process, concomitant to enzyme activity, PEPC protein and PEPC messenger RNA amounts increased considerably. This photoresponse was shown to be under phytochrome control.

Journal Article↗
PubMed1987

Morphology of scoliosis: three-dimensional evolution.

The clinical examination of the scoliotic child's profile shows that it does not correspond to the physiological curvatures. This three-dimensional study of scoliosis shows evidence of the existence of three components, frontal, sagittal, and axial. Each generates a pathological displacement of the vertebrae maximal at the apical vertebral level. Because of rotation, in order to analyze each of the components, radiographs must be taken along the frontal or sagittal plane of the vertebrae. A comparative study of the sagittal and frontal components during progression of scoliosis indicates that the apical vertebrae are displaced not only laterally but also forward and then backward. The apical vertebrae are situated anteriorly with respect to the end vertebrae. If the scoliotic curves progress, the apical vertebrae eventually become displaced backward. During this displacement at a given moment they are situated in the frontal plane of the child at the same level as the upper end vertebra; then they come to lie behind this if the scoliosis continues to progress. This explains why, when observed from the side, the appearance changes and passes through three successive stages, lordosis, flat back, and kyphosis.

Adolescent↗