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Biomedical subjects

A Masse

Publications and source records attributed to A Masse.

35 records · Page 2Linked to original sources
PubMed1985

[Passage of commercial heparin and a low molecular weight fragment of heparin, CY 222, across the placenta of pregnant rabbits].

Because of a further clinical use of low-molecular weight heparin fraction in prevention or treatment of venous thrombo-embolism, it was necessary to establish whether they cross the placenta. The studies were performed in pregnant rabbits. High doses of commercial unfractionated heparin (1 000 and 1 600 anti-Xa units per kg of body-weight) and high doses of a low molecular weight heparin fraction (1 000; 8 000 and 16 000 anti-Xa units per kg of body weight) were injected to animals at the end of gestation (term: 30 days). The placenta crossing was studied by drawing blood samples from the mother and foetus for assays of heparin blood level. There is no detectable levels of heparin in the foetus at any time after injection of commercial heparin at the dose of 1 000 anti-Xa units per kg; meanwhile heparin blood level is very low at the dose of 16 000 anti-Xa units/kg. The low molecular weight heparin fraction do not cross the placenta at the dose of 1 000 anti-Xa units/kg. However for higher doses (8 000 and 16 000 anti-Xa/kg) this heparin fraction gives a foetal heparin blood level upper than the one given by commercial heparin.

Animals↗
PubMed1984

Anatomical relationship between the medial head of the gastrocnemius and the occurrence of a dystrophic bony lacuna.

A bony lesion with identical radiological features was seen in the medial part of the distal femoral metaphysis in five patients who practised cross-country motorcycling. These findings suggested that the cause of the lesions was of muscular origin. The nature and physiopathogenesis of the lesions were studied by roentgenography, computerized tomography and analysis of anatomical specimens. The results of these procedures were compared to observations made peroperatively. The lesion was identified as a specific, dystrophic bony lacuna resulting from the action of the medial head of the gastrocnemius (caput mediale m. gastrocnemii). In certain conditions this powerful biarticular muscle induces multiple microtrauma via traction on the structures of its tendinous insertion, especially the underlying bone, thus leading to bony avulsion. It is shown in this study that the bone-tendon-muscle complex forms a veritable biomechanical unit.

Adult↗
PubMed1984

[Duodenal absorption of a low molecular weight heparin in rabbits].

Commercial heparin cannot practically cross the intestinal barrier. Meanwhile, because of the theoretical interest in oral heparin therapeutics, we applied our studies to a low molecular weight heparin fraction (3 000 to 4 000 D). This fraction was directly injected into anaesthetized rabbit duodenum. For an equal anticoagulant activity (expressed in international units), commercial heparin is not absorbed whereas the low molecular weight fraction mainly induces an early plasmatic anti-Xa activity which remains over the fifth hour.

Animals↗
PubMedDate not supplied

Calcitonin gene-related peptide receptor in human placental syncytiotrophoblast brush-border and basal plasma membranes.

Minerals, such as calcium and potassium, are essential for fetal development, but their transplacental transport, and in particular, the effect of hormones on this process has not been extensively studied. Human alpha-calcitonin gene-related peptide (h alpha CGRP), a hormone constituted of 37 amino acids, is obtained by the alternative splicing of the mRNA from the calcitonin gene, and could be implicated in placental ion transport. In order to study the presence of this receptor, brush-border and basal plasma membranes were purified, and membrane binding studies were conducted using [125I]h alpha CGRP. The initiation of binding of [125I]h alpha CGRP to both membranes was rapid and reached maximal value after 10 min of incubation at 37 degrees C. Scratchard analysis revealed single-affinity binding sites for h alpha CGRP with Kd equal to 4412.45 +/- 604.81 pM and 2673.24 +/- 552.51 pM for brush-border and basal plasma membranes, respectively, which were significantly different. Moreover, the maximal number of receptors was significantly different (P < 0.001) in both membranes, with Bmax of 627.94 +/- 31.40 fmol/mg protein for brush-border membranes and 343.70 +/- 43.52 fmol/mg protein in basal-plasma membranes. Competitive displacement of [125I]h alpha CGRP with other ligands showed the following potencies; h alpha CGRP approximately h beta CGRP approximately Cys (acm)2,7 CGRP > CGRP (8-37), but no competition was observed with human and salmon calcitonin. Half-maximal displacement for human alpha- and beta CGRP was reached at approximately 10(-10)M for brush-border and basal-plasma membranes. alpha- and beta CGRP, and their fragment and analogue, stimulated cyclic AMP production in placental homogenate ranging from 143-163 per cent. Thus, our results show the presence of CGRP-specific receptors in both the syncytiotrophoblast membranes of human placenta. The role(s) of this related peptide in placenta remains to be investigated.

Binding, Competitive↗
PubMedDate not supplied

[Treatment of chronic pain of the musculoskeletal system by epidural stimulation].

In order to reduce refractory chronic pain of the musculoskeletal system, the orthopedic surgeon can stimulate electrically the peripheral nerves or the posterior funiculi of the spinal cord (epidural neurostimulation). The authors specify their current indications for epidural stimulation in the treatment of such painful diseases: radicular pain caused by arachnoepidurites, sequelae of trauma inflicted to the spine and medulla; postoperative lomboradicular pain of mixed source, and distal lesions of the plexus brachialis. The indication for an implant stems from a rigorous strategy which requires more particularly that pain regress by more than 50% under transcutaneous neurostimulation applied for a period of least one month and that the psychological and spinal-cerebral integrity be verified. The surgical procedure comprises two stages: first, positioning of an epidural electrode and, then, insertion of a totally implantable multiprogrammable radiostimulator. Judging from a prospective assessment of 20 cases of postoperative lumbar arachnoepiduritis treated in this way, the results are considered quite encouraging.

Analgesia, Epidural↗
PubMedDate not supplied

[Experimental models of angiogenesis for the study of the Ets1 transcription factor].

The Ets1 transcription factor gene is expressed in endothelial cells during blood vessel formation under normal or pathological conditions. The proposed hypothesis aims to involve Ets1 in the regulation of angiogenesis processes by activating the transcription of genes encoding matrix-degrading proteases. In vivo experiments allowing specific manipulation of ets1 gene expression or activity within endothelial cells are necessary to investigate the functional role of Ets1. Two experimental models using retroviruses expressing ets1 mutants have been chosen: Chicken embryo development and tumour-induced angiogenesis in mice. Another approach targeted on the vascular endothelium has been developed in order to obtain transgenic mice expressing specifically in endothelial cells an ets1 transdominant negative mutant under the control of the tek and tie promoters. These tools should allow interference with Ets1 activity at defined stages during normal or pathological development.

Animals↗