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Biomedical subjects

K Ayed

Publications and source records attributed to K Ayed.

At least 109 records · Page 6Linked to original sources

[Glomerulosclerosis: myeloma or diabetes? (author's transl)].

A 52 year old man was admitted to hospital for persistent back pain, fixed proteinuria of 6g/24 h that lead to the nephrotic syndrome (proteids 40 g/l, albumin 21,2 g/l). Two possible etiologies were envisaged: 1) Myeloma with K light chains as evidenced by biological findings (absence of normal Ig, presence of K light chains both in blood and urine, malignant medullary plasmocytosis) as well as x-rays (small punched out lesions). 2. Diabetes mellitus (blood glucose 2,4 g/l) with retinal and neurological involvement. Percutaneous renal biopsy revealed nodular glomerular sclerosis compatible with both diabetes and myeloma as well as homogeneous refringent thickening of tubular basement membranes more specific of myloma. No amyloid deposits, myelomatous casts were seen and anti-K light chain fixation was negative at immunofluorescence. An evolution of 33 months duration let to chronic renal failure (plasma creatinine 47 mg/l). The respective role of myeloma and diabetes in the genesis of this glomerular nephropathy are discussed.

Biopsy↗

Experimental immune glomerulonephritis induced in the rabbit with streptococcal vaccine.

Heavy C3 glomerular deposits were observed in rabbits injected intravenously with C5 streptococcal vaccine. Immunoglobulin deposits appeared later in a few rabbits. Although some data favour the presence of circulating immune complexes during the course of this glomerulonephritis, no evidence for their initiating role could be demonstrated. Streptococcal components are known to activate the alternative pathway of complement. It is suggested that complexes made of streptococcal components and activated C3 might deposit in glomerular tufts.

Agglutinins↗

Complement receptors in human renal glomeruli. Further evidence by immunofluorescence.

A new method is described for demonstrating the presence of glomerular receptors for the third component of complement in human kidney. Frozen sections are incubated together with normal human serum and inulin. Activated C3 is detected by a fluoresceinated anti-C3 antiserum. Glomeruli are labelled by C3-coated inulin particles while there is no labelling in tubules and interstitium. This method is easy and rapid and it allows the exact localization of C3 glomerular receptors.

Animals↗

[Comparative study of technics of screening of carriers of HBs antigen].

The purpose of this study was to compare the results of 3 reverse passive haemagglutination techniques currently used by blood centers for the HBS antigen screening in donors' blood. A comparison was also made with 3 other techniques: Radio-immuno-assay (RIA), Counter-electrophoresis (CEP), Complement fixation (CF). The sera from 2.028 blood donors were screened by all those techniques, as well as 105 known sera, used as references (87 HBS antigen positive sera with different titers, 18 HBS antigen negative sera) and coming from 4 origins: NIH-Bethesda, Centre National de Transfusion Sanguine, Paris; Hôpital de la Pitié-Salpêtrière, Paris; Hôpital Broussais, Paris. The reverse passive haemagglutination techniques were shown to be slightly less sensitive than RIA and definitely more sensitive than CEP and CF, since 18 sera were HBS antigen positive with RIA (0.88%), 10 or 12 with haemagglutination (0.40-0.59%), 8 with CF (0.39%) and 7 with CEP (0.34%). The frequency of false positive results changed with the haemagglutination technique used (0.84% for WH.HBS, to 2.3% for Hepanosticon) and involved confirmatory tests (absorption and/or neutralisation). In sum, the sensitivity, specificity and practicability of the 3 haemagglutination techniques were shown to be nearly identical, with a slight but sure advantage for the WH.HBS in our experiment. Thus reverse passive haemagglutination techniques seem, at the present time, to be the best ones for HBS antigen screening when RIA cannot be applied.

Carrier State↗

Association of type 1 diabetes mellitus with the HLA-DQA1*0301 allele in a Tunisian population.

HLA class II antigens are transmembrane glycosylated heterodimers composed of an alpha and a beta chain. Several of these chains are highly polymorphic. The structural bases of the polymorphism are nucleotide acid substitutions which are situated in the first domain (exon II) of alpha and beta genes. Specific sequences of these domains can be obtained by amplification of genomic DNA using the polymerase chain reaction. Polymorphic sites are recognized by restriction endonuclease treatment and separation of the DNA fragments by polyacrylamide gel electrophoresis. The resulting fragments of different lengths are used to identify different alleles. We used the above technique for typing the HLA-DQA1 alleles in 41 Tunisian diabetic patients. The frequency of DQA1*0301 was greatly increased compared with the control group. This was in agreement with previously published data in Caucasian and Japanese insulin-dependent diabetes mellitus (IDDM) patients, while the significant increase in the frequency of the DQA1*0501 allele was comparable with that of Caucasian IDDM patients but contrasted with a decrease in this allele in Japanese IDDM patients. Our results provide confirmation of the contribution of the DQA1*0301 allele to disease susceptibility in a Tunisian population.

Alleles↗