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Biomedical subjects

J Fournier

Publications and source records attributed to J Fournier.

At least 73 records · Page 4Linked to original sources
PubMed1986

Studies on surface properties of asbestos. III. Interactions between asbestos and polynuclear aromatic hydrocarbons.

The purpose of this study is to reveal the nature of the physicochemical interactions between asbestos and polynuclear aromatic hydrocarbons (PAH) in an organic liquid medium, and to assist in the understanding of synergistic effects between asbestos and PAH in bronchopulmonary cancers. The adsorption curves of three PAH (phenanthrene, fluorene, dimethyl-7,12-benzanthracene) on chrysotile and crocidolite are multistep isotherms and show the formation of bidimensional condensed layers (2D) of PAH. This phenomenon is observed with solids having a dominant basic character (asbestos, magnesia) but is not detected with acidic solids (alumina, silica-alumina). The elimination of water and dissolved gases (O2, CO2) in the liquid medium increased the affinity of asbestos for PAH. The coadsorption CO2-phenanthrene on the substrate decreased the adsorbed quantities of solute but did not inhibit the formation of layers (2D). The adsorption is weaker on leached chrysotile, than on original chrysotile; the amorphous silica coating the fibers has no affinity for PAH; the adsorption is only due to some active sites present on the surface of residual chrysotile which is accessible to phenanthrene. The formation of layers (2D) is due to strong interactions between PAH having an induced or permanent dipole moment and the active electron donor sites present on the mineral surface. The equilibrium equation between the adsorbed layer and the PAH in solution is established by reference to theoretical studies, and the results allowed us to classify the charge density of the mineral surface. The interactions between PAH and asbestos allowed us to explain the differences introduced in the kinetics of PAH uptake toward the cells when PAH is preadsorbed on asbestos. This fact could, in part, explain the synergistic effects observed in carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1986

[Optical methods in the study of superficial displacements of the lumbar vertebrae under a vertical load. Initial results and methodological aspects].

In order to assess superficial displacements under load in human lumbar vertebrae, the authors used three different optical methods: photogrammetry under non coherent light; double-exposure holographic interferometry; speckle granularity under laser exposure. Without any structural interposition, the displacements are measured within 10 mu for linear variations and 0.1 degrees for angular variations. Photogrammetry seems to be more adequate for the study of large range of displacements while holographic and speckle techniques are useful to assess, in the displacements, the part of the disc and the osseous structure deformation respectively.

Biomechanical Phenomena↗
PubMed1981

[Study of the talus and calcaneus using microdurometry, penetrometry and compression].

The authors give the results of various methods such as hardness micrometry, indentation tests and the radiographic study of fracture patterns, which they have applied to the talus and to the calcaneus. It appeared to them that: --these techniques outline the phenomenon of rupture behaviour of both talus and calcaneus; --the talus behaves as a fragile type of material whereas the calcaneus is of the intermediate type. The authors therefore think that these methods can be of great interest in a better understanding of the biomechanical properties of bone.

Biomechanical Phenomena↗
PubMed1980

[Peroxidation of lipids in the inflammatory process].

Lipidoperoxidation in the sebum from 10 subjects suffering from inflammatory acne has been shown by use of mass spectroscopy, in contrast with 10 normal subjects where this was not observed. Peroxidation of sebum lipids is probably linked with the inflammation of the comedons.

Acne Vulgaris↗
PubMed1980

[Recurrent nasal polyposis and vidian neurectomy - preliminary report].

A short anatomical and physiological review of the vidian nerve is presented. The authors have described the surgical technique they use which is somewhat similar to the one described by Nomura. Eight cases are presented which had been unsuccessfully treated by multiple radical nasal polypectomies. The results are comparable to those published in the literature and it appears that vidian neurectomy has merit in the treatment of recurrent nasal polyposis but must be used in association with radical polypectomy.

Denervation↗
PubMed1979

Neurilemmoma of the parapharyngeal space. Report of three cases and review of the literature.

The clinical pre-operative diagnosis of parapharyngeal neurilemmoma is frequently missed. Bimanual palpation of the mass is the most rewarding clinical investigation. Intra-oral incisional biopsy is to be prescribed in case of benign tumor. Treatment is achieved by total excision by external approach. Recurrence rates in benign lesions are low but high with malignant tumors. Three cases of parapharyngeal neurilemmoma are presented.

Adult↗
PubMed1979

[Equilibrium of thiamine diphosphate complexation with divalent ions--formation constants].

The divalent metal ion-thiamine diphosphate (TDP) complexes are of potential interest because such complexes are directly involved in enzymatic reactions. The binding of Ni2+ to TDP has been studied in order to gain some insight in the TDP-metal interactions which could help to understand the role of the metal ions in general in the enzymatic processes. A technique of pH titration is developped which brings definitive proof of metal-TDP bonding in aqueous solutions. The results indicate that the metal ion interacts both with the pyrophosphate group and the pyrimidine ring. The complexation decreases the pK for the phosphate ionization. The ring nitrogen is a some 12 times weaker ligand of Ni2+ than is pyrophosphate. The stability constants obtained for an ionic strength 0.5 in tetramethylammonium bromide are reported; the maximum of the apparent formation constant, between pH 4.5 and pH 7.5, occurs for pH 6.9. The poor solubility of nickel hydroxyde is responsible for increasing interaction in alcaline solution.

Binding Sites↗
PubMed1975

[Rupture of the spleen in patients with multiple injuries. Current diagnostic methods. Apropos of 60 cases].

The authors report 60 cases of severe multiple injuries and study present methods permitting a rapid diagnosis of latent rupture of the spleen. Purely clinical methods are today supplemented by paraclinical investigations. e.g. --intra-abdominal catheterisation; --peritoneal wash-out; --laparoscopy; --and, above all, arteriography. The authors use these methods and weigh the advantages and disadvantages of each.

Abdominal Injuries↗