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Biomedical subjects

F Lemarchand

Publications and source records attributed to F Lemarchand.

At least 19 recordsLinked to original sources
PubMed2000

Dipole radiation into grating structures

We present a detailed electromagnetic analysis for the radiation of an electric source located inside grating structures. Our analysis is based on the differential method and uses the scattering-matrix algorithm. We show that gratings that exhibit periodic modulations along two spatial directions (crossed gratings) enable one to couple out the totality of the light emitted by the source into the guided modes of the structure. This property is investigated through the computation of the far-field radiation patterns for crossed gratings with various etching depths. One key result is the possibility to confine the emitted light in a direction about the sample normal, a property that is of interest in the context of spontaneous emission control by microcavity structures.

Journal Article↗
PubMed1992

[Hemangiomas and superficial vascular malformations: classification].

Superficial vascular malformations of the face, trunk and limbs are better known today, and they can be divided up into simple and complex vascular malformations. Simple vascular malformations may form five major categories: immature hemangiomas of infants, port-wine stains, capillarovenous angiodysplasias, and arteriovenous fistulae and malformations. Complex angiodysplasias are systematized (Sturge-Weber and Bonnet-Dechaume-Blanc syndromes, Cobb's metameric angiomatosis, Klippel-Trenaunay and Parkes Weber's syndromes) or disseminated (Weber-Osler-Rendu disease and blue rubber-bleb nevus syndrome). Various modalities of treatment may be contemplated, according to the type of malformations, and an interdisciplinary consultation is essential to decide whether a watch-and-wait policy, a physical method (laser), embolization, fibrosing injections, vascular, maxillofacial or plastic surgery, or a successive combination of various techniques should be resorted to.

Angiodysplasia↗
PubMed1992

[Exploration strategy for superficial vascular malformations].

Transillumination of cystic lymphangiomas, MRI of venous vascular malformations, pulsed Doppler and arteriography of arteriovenous malformations, echo-Doppler and radiomeasurement of malformations in the lower limbs are key examinations in the exploration strategy for superficial vascular malformations.

Adult↗
PubMed1991

HLA DQB1*0301 allele is involved in the susceptibility to erythema multiforme.

Erythema multiforme (EM) is an acute, episodic inflammatory disorder of the skin and mucous membranes of various etiology that could be related to immunologic hypersensitivity response. EM has been previously reported to be associated with serologically defined HLA-DRw53 and DQw3 antigens. In this report, we reevaluate the role of HLA class II alleles in EM manifestations. With use of the polymerase chain reaction, followed by sequence-specific oligonucleotide hybridization, 35 unrelated Caucasian EM patients and 80 randomly selected healthy subjects were studied, and the DRB3, DRB4, DQA1, and DQB1 alleles were analyzed. The comparison of frequencies of these alleles indicates that (i) susceptibility to EM disease is more associated with the HLA-DQ than the HLA-DR subregions and (ii) that the DQB1*0301 is the most frequent allele among EM patients. Sixty-six percent of the patients had the DQB1*0301 allele compared to 31% of the controls (RR = 4.1; p less than 0.001). An even stronger DQB1*0301 association was found in the patient group with herpes-associated EM (76%; RR = 6.5; p less than 0.001). Our data demonstrate a clear association between an HLA-DQB1 allele and susceptibility to EM.

Adolescent↗
PubMed1989

Chronic urticaria and macroglobulinemia (Schnitzler's syndrome): report of two cases.

Two cases of chronic urticaria associated with macroglobulinemia are reported, and the characteristics of 13 other cases are reviewed. This entity was described by Schnitzler in 1974 and has the following characteristics: chronic nonpruritic urticaria with leukocytoclastic vasculitis, bone pains with hyperostosis, intermittent fever, and a monoclonal IgM gammopathy. Liver, lymph node, and spleen enlargement may occur. Criteria for the diagnosis of Waldenström's disease are lacking (IgM level less than 10 gm/L, no overt lymphoid proliferation in bone marrow). Other immunologic findings (complement, C1 inhibitor, cryoglobulin, rheumatoid factor, antinuclear antibodies) are negative or normal. Evolution is long-term with a long follow-up period. In one case a lymphoplasmocytic lymphoma developed. No adequate treatment has yet been found. Pathogenesis is unclear but seems to be caused by skin deposits of the IgM paraprotein, as attested to by the direct cutaneous immunofluorescent findings in some cases.

Bone Diseases↗
PubMed1988

Erythema multiforme is associated to HLA-Aw33 and DRw53.

Erythema multiforme is an acute eruption of the skin and mucous membranes of various aetiologies. Forty-one unrelated patients were HLA typed for 53 specificities of the HLA-A, B, C, DR and DQ series. Frequencies of Aw33 and DRw53 were significantly increased: Aw33, 17.0% in patients vs 2.8% in controls (corrected p = 0.01, relative risk = 7.2); DRw53, 70.7% in patients vs 30.5% in controls (corrected p = 0.0005, relative risk = 5.5).

Adult↗
PubMed1983

[Foreign bodies in the biliary tract. I. Postoperative foreign bodies in the biliary tract. Review of the literature (71 cases) apropos of 4 personal cases].

Starting out from four cases which they personally treated, the authors have made a complete review of the literature concerning biliary foreign bodies, and list 92 cases, with the following breakdown - 71 operative residues, 15 ingested bodies and 6 penetrating bodies. They attempt to analyse the mechanics of the formation of lithiasis around post-operative residues and assess its real frequency. They come to the following conclusions: most of these cases can be avoided by careful cleaning before closure of the choledocotomy, by the use of good-quality, correctly cut T-tubes and drainage material, by cutting the cystic duct as short as possible, and by exclusive use of resorbable fine thread in the biliary tract and the cystic artery.

Adult↗
PubMed1983

[Foreign bodies in the biliary tract. II. Unusual foreign bodies in the biliary tract. Review of the literature].

The authors have collated 21 cases of unusual foreign bodies, other than parasites, in the biliary tract. The collection includes 6 penetrating bodies, 4 ingested by patients who had undergone previous bilio-digestive anastomosis or a sphincterotomy, and 11 foreign bodies ingested by patients who had never had previous surgical treatment. They consider that the real frequency is certainly greater than might be expected from a review of the literature. They discuss the different ways of penetrating the biliary tract and stress the interest of wide biliodigestive anastomosis and large Y loops, as recommended by Roux, to prevent lithiasis forming on food residue trapped at the level of the anastomosis or upstream.

Biliary Tract↗
PubMed1981

[Thymoma associated with myasthenia, erythroblastopenia, myositis and giant cell myocarditis. One case (author's transl)].

The authors report on a 76-year-old woman presenting with malignant thymoma associated with myasthenia, erythroblastopenia, myositis and giant cell myocarditis. Blood examination showed antinuclear antibodies, anti-platelet antibodies and LE cells. Only one similar case and 22 cases of thymoma associated with giant cell myocarditis have been published. It seems probable that thymomas plays a part in the pathogenesis of giant cell myocarditis.

Aged↗