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Biomedical subjects

P Mercier

Publications and source records attributed to P Mercier.

At least 145 records · Page 8Linked to original sources
PubMed1990

Topographic anatomy of the lumbar lateral vertebral groove. Anatomical basis of the surgical approach to extra foraminal herniated disc.

The study of numerous dissections, sections and X-rays of the lumbar spine has enabled us to clarify the connections of the lumbar spinal nerves at their emergence from the intervertebral foramen and in the lateral vertebral groove. This work naturally leads to the study of the extra foraminal herniated disc by an extra isthmian approach or to percutaneous surgery of thoracolumbar discs.

Humans↗
PubMed1990

[Collagen type IV: major component of basement membranes. Current knowledge].

The collagen family represents the most abundant protein in animals. Type IV collagen ([alpha 1 (IV)]2 alpha 2 (IV)) differs from the other types in several respects and particularly in its distribution, being strictly limited to the basement membranes. Alterations in the structure and functions of basement membranes are observed in a number of diseases, such as tumoral angiogenesis and diabetic nephropathy. This article reviews current structural and pathophysiological knowledge concerning type IV collagen.

Basement Membrane↗
PubMed1990

[Good tolerance and absence of immunologic effects in mice treated with arsenic-rich thermal water].

Three strains of mice were given, per os and ad libitum, a spa water containing 6.8 mg/l arsenic and indicated for the treatment of allergic respiratory diseases or chronic bronchitis. The daily arsenic intake was approximately from 1.5 to 4 mg/kg. No effect on body weight gain or on the various immune parameters assessed was observed. These results demonstrate that this spa water, despite its high arsenic content, is not toxic and does not interfere with the immune system of healthy mice.

Animals↗
PubMed1990

Ridge reconstruction with hydroxylapatite: potential and shortcomings.

Residual ridge resorption leading to masticatory difficulties does not only modify eating habits but may also affect the gastrointestinal system. Facing such a serious problem, the dental profession has the responsibility of proposing effective methods that can be applied to most individuals. Over and above socio-economic reasons, ridge reconstruction with hydroxylapatite has other distinct advantages over implants. This material does preserve the residual bone as it is placed over existing structures without any bone loss, and can thus be applied to any atrophy case. It can be molded to create a very retentive ridge form for dentures and to correct abnormal ridge relationships. Finally, it is totally isolated from oral microbiotics. Most of the complications reported can be avoided by proper surgical techniques. The most serious one is occasional resorption of the material itself for which newer osteogenic materials now in the process of being developed might afford a solution.

Alveolar Ridge Augmentation↗
PubMed1990

[Platelet antibody activity in malaria thrombocytopenia].

To assess immune responses to malaria-induced thrombocytopenia, an haematologic and immunologic study was performed on 25 patients with imported malaria upon admission and 8 days after treatment. Thrombocytopenia (150 x 10(9)/litre) was detected in 19 cases (P. falciparum: 11 cases, P. ovale: 6 cases, P. vivax: 2 cases). No laboratory evidence of disseminated intravascular coagulation impairment was found in any of the patients. Bone marrow examination performed in 9 cases showed no abnormality in the megakaryocyte series. Platelet count was independent of circulating parasite levels (r = 0.27) and inversely related to the number of antibody binding sites (ABS) on platelets (r = -0.6, p. less than 0.01). The indirect Coombs test (r = -0.54; p less than 0.01) and IgG and IgE levels (p less than 0.02) gave similar findings. A statistical correlation was observed between the level of circulating immune complex and the number of ABS (r = 0.525, p less than 0.01). Thus malaria-induced thrombocytopenia seems to mainly involve IgG type antiplatelet antibody activity. Although they may be implicated in the binding of antibodies to platelets, circulating immune complexes do not appear to mediate thrombocytopenia.

Adolescent↗
PubMed1989

IFN-mediated differential regulation of the expression of HLA-B7 and HLA-A3 class I genes.

The regulation by IFN of the expression of HLA-B7 and HLA-A3 class I molecules was studied in Jurkat human T lymphoma cells, HHK EBV-transformed human B lymphocytes, and murine HLA-B7 HLA-A3 co-transfected L fibroblasts. Jurkat cells express constitutively low level of HLA class I molecules and treatment with human IFN resulted in preferential increase of the expression of HLA-B7 molecules, the expression of the HLA-A3 molecules being relatively unchanged. Similar treatment of HHK cells, which express constitutively large amount of HLA class I molecules, resulted in a marginal increase of the expression of both HLA-B7 and HLA-A3 molecules. HLA-B7 HLA-A3 co-transfected L cells express relatively low level of HLA class I molecules, expression of both however was significantly increased after treatment with murine INF-alpha, the augmentation being more accentuated for HLA-B7 molecules. In all cases, variations of cell surface expression were related to parallel modifications of the level of HLA-B7 and HLA-A3 RNA transcripts. Important nucleotide differences exist between the IFN consensus sequences associated with the HLA-B7 and HLA-A3 class I genes. Using oligonucleotides corresponding to these sequences two patterns of retarded bands were observed by the gel mobility shift assay, suggesting that the IFN-mediated differential regulation of the expression of the HLA-B7 and HLA-A3 genes could be due to different nuclear regulatory factors.

Adjuvants, Immunologic↗
PubMed1989

The principal artery of the psoas major muscle.

The psoas major m. has a complex arterial supply, derived from the lumbar, iliolumbar, obturator, external iliac and common femoral a. The branches arising from the external iliac a., though quite often multiple and slender, are represented in 75% of cases by a single large-caliber vessel. This principal artery of the psoas m. is probably responsible for the curves of the external iliac a. in the aged and also in certain competitive athletes.

Age Factors↗
PubMed1989

A rare embryologic variation: carotid-anterior cerebral artery anastomosis or infraoptic course of the anterior cerebral artery.

Carotid-anterior cerebral artery anastomosis constitutes an anomaly of the anterior part of the arterial circle of the brain. The anterior cerebral a. arises a few millimeters above the emergence of the internal carotid from the cavernous sinus, at the usual level of origin of the ophthalmic a. It travels medially, beneath the optic n., and then describes a curve with a superolateral concavity to arrive at the anterior part of the optic chiasma, where it anastomoses with the anterior communicating a. This asymptomatic variant of course is often associated with other cerebral vascular anomalies, especially arterial aneurysms. On the basis of 2 new cases discovered by chance, together with a review of the literature, various hypotheses capable of explaining the embryologic origin of these anomalies are discussed.

Adult↗
PubMed1989

Surgical and prosthodontic residual ridge reconstruction with hydroxyapatite.

The ultimate goal of a ridge augmentation procedure is to form a bearing surface for the denture that will provide stability, retention, and support. Residual ridge reconstruction with an implanted material must be based on an understanding of the variations of ridge atrophy. A problem-oriented classification describes the different forms of residual ridges. This classification of similar types of resorbed residual ridges can be used to establish a rational plan of treatment. The proper placement of hydroxyapatite is critical to obtain the desired reconstructed residual ridge. In the mandible, a lingualized placement of the alloplast is suggested. Careful use of an anatomic matrix to support and contain the hydroxyapatite particles eliminates the need for a splint. The surgical stage includes vestibuloplasty and skin grafting to provide the patient with an increased denture-bearing surface. The ridge created in the form of a comma posteriorly enhances retention and stability. The broad residual ridge with an improved interarch relation also enhances the support and provides a better foundation for balanced occlusion.

Alveolar Process↗
PubMed1989

Repair of trabecular fatigue fractures. Cadaver studies of the upper femur.

The healing process and the distribution of trabecular fatigue fractures were studied on upper femora obtained at autopsy. Macroscopically, two main types of trabecular fatigue fractures were found on the basis of callus formation that in histologic sections were composed of woven and lamellar bone. A third type characterized by its vestigial callus was found only in histologic sections. Fatigue fractures were more numerous in regions of the femoral head submitted mainly to compressive rather than tensile stress. Trabeculae submitted to compressive stress had a majority of the type of fatigue fractures with an exuberant thorny callus composed of woven bone (most of them located subjacent to the subchondral bone plate), whereas trabeculae submitted mainly to tension or to minimal stress, as in Ward's triangle, had a majority of fatigue fractures with a small, smooth-surfaced callus composed of lamellar bone.

Adult↗
PubMed1989

[Intracerebral graft of a line of chromaffin cells. Immunologic aspects and role of nerve growth factor in survival and differentiation of the graft].

The efficiency of neuronal grafts is correlated with the differentiation of the grafted cells and the connections they establish with the host tissue. The prolonged survival of a chromaffin cell line (PC12) transplanted into an immunodepressed rat brain shows that neuronal differentiation is correlated with the amount of nerve growth factor (N.G.F.) present in the grafted structure. This result is in agreement with in vitro studies. The characterization of other factors that influence the differentiation of PC12 cells in culture could lead to an increase in the efficiency of intracerebral grafts of adrenal medulla cells in Parkinson's disease.

Adrenal Gland Neoplasms↗
PubMed1989

[Spinal osteoid osteomas. Apropos of 4 cases].

Spinal osteoid osteomas constitute a rare but perfectly curable cause of non-disc root pain. In discussing four cases (2 cervical and 2 lumbar), the authors stress that this disorder affects above all males under 30 and presents as vertebral column pain gradually becoming radicular in character; the pain, essentially nocturnal, is spectacularly but transiently relieved by salicylates and is accompanied by often frank stiffness of the spine. The diagnosis is based less on X rays and tomographs, than on isotope bone scanning, which reveals a focus of intense hyperfixation, and CAT scanning which shows a bony lacuna possibly with an opacity in the center producing a rosette shaped image. Block excision of the osteoid osteoma produces immediate relief for the patient and prevents recurrence which only occurs exceptionally.

Adult↗
PubMed1988

Scanographic study of the calcaneus: normal anatomy and clinical applications.

To facilitate the interpretation of the scanographic findings in fractures of the calcaneus, the authors have achieved an anatomo-radiologic correlation in terms of the classical coronal, sagittal and horizontal planes. Clinically, the sagittal plane can be obtained only by reconstruction. The 2 other planes permit study of the sustentaculum tali and posterior talar surface only in different sections, without their respective relationships. The authors therefore suggest a new double-oblique view, practicable in the injured patient, with a forward tilt of 20 degrees and medial rotation of 35 degrees, perpendicular to the sinus tarsi. This serves for anatomo-radiologic correlation and shows both anatomic structures together. By itself, it provides as much information as the three classical views and appears adequate for the assessment of fractures.

Calcaneus↗
PubMed1988

Ridge reconstruction with hydroxylapatite. Part 2. Ridge reconstruction based on residual anatomic structure.

The second part of this article shows how the problems of atrophy and resorption of the residual ridge can be corrected with hydroxylapatite to obtain ideal ridge form and maximal prosthetic rehabilitation. The high degree of efficiency of the system is based on a thorough knowledge of the anatomic structures involved, on the use of the cephalogram as a guide, on the correction of adverse intermaxillary relationships and on the recourse to a staging of procedures when required.

Alveolar Process↗