Mise en évidence et évaluation des “moyennes molécules” de la taille de la vitamine B12 présentes dans les liquides biologiques de sujets normaux et de patients urémiques

Molecules in the Middle Molecular Weight Range

“…Funck-Brentano and co-workers followed up a fraction from uremic serum which inhibited in vitro nervous con duction in isolated frog nerve [14,21,22,42,44]. After having tried various chromatographic systems [21,44], it appears that the authors [22] changed to a technique derived from that of Fürst et al [24] for the rapid testing of small quantities of serum (separation on Sephadex G15, then DEAE Sephadex A25 on microcolumn but using experiment conditions different from those used by Fürst et al).…”

“…Biological fluids were collected from various types of CRF patients, according to the different studies: nondialyzcd patients [14,17,18,24,27,28,41,42,46,[49][50][51]57]; patients dialyzed by different techniques: peritoneal dialy sis [24,28], hemodialysis [1-3,12,14,17,21,24,28,29,31,41, 44.45.50.53.55.57] ; dialyzed patients developing pericar ditis [24,55] or polyneuritis [14,21,24,44]; or CRF pa tients with high levels of creatinine urea [1][2][3]7],…”

“…Among the various studies, the fluids analyzed were (table I): serum or plasma of normal or uremic subjects [12, 14, 17, 18, 22, 24, 27-29, 31, 36, 39, 41, 45, 46, 49, 50, 53.55.57] ; urine [12,14,18,21,24,28,40,42,46,[49][50][51]57]; dialyzates obtained from dialysis on different types of membrane [1, 10,12,14,28,31,[44][45][46]53,54] and under var ious conditions: opened [53,54] or closed [53] dialysis, hemoperfusion [41], ultrafiltration [53,60], collection of dialyzate during the first 30 min of dialysis [34] or after 2 and 24 h [24]; cerebrospinal fluid [41]; pericardial fluid [41].…”

“…The fluids were often ultrafiltrated on calibrated mem branes before analysis, permitting the elimination of either low-MW substances (Amicon Diaflo UM 05, cutoff: 500 daltons) [1, 3,10,17,29,46] or proteins: Amicon Diaflo PM [24,28]; Millipore Pellicon PSAC (cutoff: 1,000) [14], PSED (cutoff: 25,000) [53]; Rhône-Poulenc AN 69 (cutoff: 20,000) [14,22], polyacrylonitrile (cutoff: 30,000 daltons) [21].…”

“…The determination of the MW of fractions of chroma tography was carried out, in the majority of cases, by calibrating the column with substances of known MW 196 Contreras/Later/Navarro/Touraine/Freyria/Traeger (most often Vitamin Bi>, oligopeptides...) [10,12,14,26,27,29,34,36,39,41,45,50,53] or by using ultrafiltration mem branes with a known cutoff [10,14,22,46]. According to the groups, the estimated MWs range from 500 to 5,000 daltons [ 17,22,26,27,29,31,39,41,60],…”