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Biomedical subjects

C Vincent

Publications and source records attributed to C Vincent.

At least 253 records · Page 14Linked to original sources
PubMed1985

Complexes of alpha 1-microglobulin and monomeric IgA in multiple myeloma and normal human sera.

alpha 1-Microglobulin (alpha lm), a glycoprotein heterogeneous in charge, was reported to occur both as a 31-kilodalton (kd) monomer [low mol. wt alpha lm (LMW-alpha lm)] and as polymers or complexes formed with other plasma proteins including IgA [high mol. wt alpha lm (HMW-alpha lm)]. The present study was designed to characterize HMW-alpha lm in normal human serum and in myeloma sera. The following sera were selected: five IgG, 16 IgA and four Bence-Jones protein myelomas. alpha lm was identified by specific monoclonal antibodies in competitive radioimmunoassay and solid-phase ELISA. HMW-alpha lm was found to be associated almost exclusively with monomeric IgA and possibly in very small proportion with dimeric IgA. Ever in cases of predominantly dimeric IgA myelomas, alpha lm was associated with the monomeric form of the monoclonal IgA. The molar ratio of HMW-alpha lm to monomeric IgA never exceeded 3.5% and it was estimated to range from 0.5 to 1.4% in normal serum. No association with other proteins than IgA and no alpha lm polymers were found in IgA myeloma. Two types of HMW-alpha lm-IgA complexes were found: (a) those that were dissociable into IgA and LMW-alpha lm after mild reduction, and (b) those which were dissociated only after complete reduction of the complexes into IgA and an 88-90-kd component bearing alpha lm but no IgA epitopes. It was concluded that either of the two molecular species of alpha lm bearing common epitopes, with apparent mol. wts of 31,000 and 88,000-90,000, respectively, could form stable complexes with monomeric IgA. The association is likely to be performed through disulfide bridges. Nearly all the 88-90-kd but only a small proportion of the 31-kd component is associated with IgA.

Alpha-Globulins↗
PubMed1985

A collaborative study of a preparation of normal human serum for use as a reference in the assay of beta 2 microglobulin.

A biological standard for beta 2 microglobulin (beta 2m) determination has been prepared from pooled human serum by sampling and freeze-drying. A preliminary study of parallelism between the dose-response curves of the preparation and pure beta 2m or biological fluids was made with four different methods of assay and gave satisfactory results. In a collaborative study in five laboratories in five countries using a common method of assay, evidence was obtained that the preparation coded 80-12-3200 was suitable to serve as a standard for the assay of beta 2 microglobulin. Criteria included the constancy of the amount of material per vial and the stability of the freeze-dried product. The technique used for beta 2m determination was a radioimmunoassay.

Drug Stability↗
PubMed1985

[Acute renal failure after extracorporeal circulation with aortic counterpulsation in surgically treated patients].

In a series of 604 adults operated on for cardiac surgery with cardiopulmonary bypass (CPB), 21 (3.5%) underwent circulatory assistance by intra-aortic balloon pump (IABP); in 5 of them (24%), acute renal failure (ARF) was observed. ARF occurred in only 26 (4.4%) of the other patients who did not require IABP. Evolution of ARF and its factors were therefore investigated in those patients having received IABP. ARF was defined as serum blood urea nitrogen (BUN) greater than or equal to 16 mmol X 1(-1), urinary urea/BUN less than 10, creatinine clearance less than 40 ml X min-1 X 1.73 m-2. Some perioperative features were compared between patients with postoperative ARF and those without ARF. ARF occurred in the 5 patients with IABP during, or immediately after, weaning from IABP. ARF was more frequent in patients operated on for mechanical complications of myocardial infarction with a significant more severe haemodynamic status. They had significantly longer CPB and aortic clamping times. The prognosis depended on the cardiac failure and not on the ARF. In patients with mechanical complications of infarction, early IABP seemed to be the predominant preventive measure. Other therapeutic implications are suggested, particularly the use of dopamine (1 to 3 micrograms X kg-1 X min-1) because of its renal vasodilating action which can contribute to the maintenance of urinary flow.

Acute Kidney Injury↗
PubMed1985

Alpha 1-microglobulin: a new antigenic component of the epidermo-dermal junction in normal human skin.

Monoclonal antibodies to human alpha 1-microglobulin (alpha 1-m), a glycoprotein present in most biological fluids, reacted with the basement membrane of the epidermo-dermal junction and that of eccrine sweat glands in normal human skin. This immunofluorescence was specific in that control antibodies of known well-defined reactivity did not stain these structures. Therefore, alpha 1-m seems to be a new antigenic component of the junction and it may be an interesting antigen to study in diseases of this area.

Alpha-Globulins↗
PubMed1984

Localization of alpha 1-microglobulin (HC protein) in normal human tissues: an immunohistochemical study using monoclonal antibodies.

Alpha-1-microglobulin is a low molecular weight (approximately 30 000 d) glycoprotein present in biological fluids. It is heterogeneous in charge. A monoclonal antibody was used to investigate the tissue distribution of the protein in normal human tissues and cell lines by indirect immunofluorescence and immunoperoxidase techniques. The protein was demonstrable in cells of the monocyte-macrophage lineage, in thymus and T cell dependent areas of spleen, lymph node and tonsils. It was detected in several lymphoid or nonlymphoid cell lines but not in peripheral blood lymphocytes. The microglobulin was also detectable in the cytoplasm of hepatocytes. Finally, it was observed in glandular secretions (sudoral glands and mucosal glands of the digestive tract) where it may be associated with IgA. Possible explanations for the highly divergent results previously reported with polyclonal antisera to alpha 1 microglobulin are discussed.

Alpha-Globulins↗
PubMed1984

[In vitro study of the influence of dorsal bodies on oogenesis in Helix aspersa Müll].

Infantile gonads of Helix aspersa were cultured in vitro for 13 days, alone, associated with dorsal bodies, or with cerebral ganglia (surrounded by connective tissue containing the dorsal bodies). The results demonstrate the stimulatory effect of the dorsal bodies on oocyte growth and suggest that the cerebral ganglia have an inhibitory influence on dorsal body activity and/or on oocyte development.

Animals↗
PubMed1984

Participation of encephalitogen in incomplete Freund's adjuvant in the induction of experimental allergic encephalomyelitis in Hartley guinea pigs.

The addition of complete Freund's adjuvant (CFA) to encephalitogen is required for the induction of experimental allergic encephalomyelitis (EAE). On the other hand, administration of encephalitogen in incomplete Freund's adjuvant (IFA) protects the animal from the development of EAE. It is shown in this work that injection of homologous central nervous system (CNS) tissue or myelin basic protein (BP) in IFA, before challenge with CNS tissue in CFA, accelerated the onset of the disease in Hartley guinea pigs. It also appeared to protect the animals, however, because 22% of the group did not develop EAE at all, and in those which did, the disease was not as lethal as in controls. To produce this accelerated form of EAE with encephalitogen in IFA required (1) a time interval shorter than 9 days between the first injection and challenge and (2) that the first injection and the challenge be done in the same site, which could be hind or front foot pads but not the nuchal area. The results indicated that 'priming' by encephalitogen in IFA occurred when this two-step induction procedure was used. The experimental conditions may have bypassed suppressive mechanisms.

Animals↗
PubMed1984

Renal tubular absorption of beta 2 microglobulin.

125Iodinated human beta 2 microglobulin (beta 2m, 5 to 30 mg) was administered to anesthetized rats. Clearance studies showed a low threshold of excretion of injected beta 2m and a high Tm of 400 to 600 micrograms X min-1 X kg-1. A glomerular sieving coefficient of 0.97 was calculated as the slope of the curve: beta 2m excretion rate = F (plasma beta 2m X glomerular filtration rate) for values above saturation. Electrophoresis analysis of proteinuria in agarose gel and sodium dodecyl sulfate polyacrylamide gel showed that injection of saturating doses of beta 2m induced the excretion of proteins of similar size but different charge and that of other proteins of different size. Among the latter, some were excreted transiently in association with beta 2m, whereas others had a delayed excretion suggesting existence of a complex mechanism of reabsorption whose steps remain to be elucidated.

Absorption↗
PubMed1984

Immunohistological localization of alpha 1-microglobulin in normal rat tissues.

The tissue distribution of rat alpha 1-microglobulin (alpha 1-m) was studied by indirect immunofluorescence in various rat tissues using a polyvalent rabbit antiserum to the purified antigen and a monoclonal antibody (H23) to the human homologue, in parallel with a polyclonal anti-rat IgA antiserum. It was found that all tissues stained by anti-IgA were also alpha 1-m positive; these tissues included tissues of the stomach, duodenum, ileum, colon, pancreas, trachea, esophagus and jejunum. However, the observation that IgA plasma cells as well as secretory cells, while positively stained by anti-IgA, are alpha 1-m negative suggests that the association between IgA and alpha 1-m occurs at a postsecretory stage, after the IgA molecules have been transported across the epithelial cells. Additionally, hepatocytes were intensely stained by anti-alpha 1-m antibodies, indicating that the liver, as already suggested by metabolic studies on isolated guinea-pig liver explants, may be responsible for the synthesis of this protein. Among lymphoid tissues, an intense and homogeneous staining was observed in the thymus and the white pulp of the spleen. Sections of lymph nodes, however, showed differential staining; apart from a few isolated dendritic cells in the mantle region of the lymphoid follicles, the germinal centers and medullary cords showed no staining with anti-alpha 1-m antibodies. The paracortical cells, macrophages in the subcapsular sinus, and interfollicular lymphocytes showed intense cytoplasmic staining with anti-alpha 1-m antibodies. In other tissues, macrophages, monocytes, tissue histiocytes, and dendritic cells were alpha 1-m positive. Although they confirm the presence of alpha 1-m in the lymphoid tissues, as already reported in man, these results show that the protein is also present in hepatocytes and in exocrine fluids containing IgA. Since alpha 1-m, like secretory component, can bind to IgA to form stable complexes, these two heavily glycosylated proteins may have similar biologic properties.

Alpha-Globulins↗
PubMed1984

Morphologic, quantitative and cytoenzymologic studies of synoviocytic and monocytic cells in synovial fluid.

The findings are presented of a morphologic, quantitative, cytochemical and cytoenzymologic study of the mononucleated nonlymphoid cells in knee synovial fluids from osteoarthritis and various inflammatory diseases. The morphologic criteria allowed the identification of subtypes, including phagocytic subtypes, among synoviocytic and monocytic cells in the fluids. The quantitative study showed an important afflux of monocytes and a hyperexfoliation of synoviocytes in the inflammatory diseases. In fluids with intermediate cellularity, the ratio of monocytes to synoviocytes allowed the differential cytodiagnosis between osteoarthrosis and arthritis. All monocytic subtypes, especially the phagocytic one, were highly significantly increased in the inflammatory diseases. A lower increase was shown by the synoviocytic subtypes, except the phagocytic one, which was not changed. Giant multinucleated synoviocytes were found in every type of disease and thus do not constitute a cytodiagnostic marker. Alcian blue staining without hyaluronidase treatment showed hyaluronate in only a small percentage of the synoviocytes. Cytoenzymologic study showed that synoviocytes and monocytes were positive for all tested hydrolases (beta glucuronidase, acid phosphatase and alpha naphthyl acetate esterase), with the reactivities always higher in the synoviocytes. The synoviocytes were always negative with peroxidase, so this reaction, although it marks only a minority of the monocytic population, can be used as an extra cytologic criterion for the discrimination of mononucleated cells in synovial fluid. There was no significant quantitative difference at the cellular level between osteoarthrosis and arthritides in the reaction to these four enzymes. The lysosomal enzymatic activity in both monocytic and synoviocytic cells confirmed their heterophagic properties. However, synoviocytic heterophagy seems to be a physiologic process, either little or not affected by inflammatory events. On the other hand, monocytic heterophagy and then the macrophagic transformation of monocytes appears to be a major aspect of intrasynovial inflammatory reactions. The question remains as to why, if a large majority of exfoliated synoviocytes comes from type A synovial-lining cells and if they belong to mononuclear phagocytic system, do they so weakly, or not at all, participate as phagocytes in the inflammatory reaction.

Acid Phosphatase↗
PubMed1984

[Incidence and prognosis of acute renal failure after cardiac surgery with extracorporeal circulation].

Acute renal failure occurred in 21 patients after 311 cardiac operations with cardiopulmonary bypass in adults (6,75%). It was non oliguric in 20 cases. It is related to per and postoperative hemodynamic depression. Patients operated for valvular replacement seemed most at risk if severe cardiac failure existed with or without preoperative renal dysfunction. Similarly those operated upon for mechanical complications of myocardial infarction were often affected. The prognosis depends on the degree of cardiac failure. Strict patient selection, myocardial protection during bypass and measures to increase low cardiac output are recommended. Intra-aortic balloon pump for patients with myocardial infarction and dopamine in the early postoperative period seem helpful.

Acute Kidney Injury↗
PubMed1983

Characterization of rat alpha 1 microglobulin.

A molecule heterogeneous in charge with an apparent MW of 30 000 d and associated chromophore and carbohydrate was isolated from rat urine. When compared to human alpha 1-m its fluorescence spectra as well as staining pattern on agarose gel electrophoresis or electrofocussing were very similar. Furthermore, the specific antiserum prepared against the molecule detects an antigenic determinant also detected by monoclonal antibodies against human alpha 1-m. For these reasons this protein can be considered as the rat equivalent of human alpha 1-m.

Alpha-Globulins↗
PubMed1983

Auto-antibodies specific for beta 2 microglobulin in normal human serum.

Serum components with binding activity towards free human beta 2 microglobulin (beta 2m) were investigated in healthy adults. The binding activity increased after treatment of the serum components by dissociating buffers (acid pH, 2-8 M urea, 3 M NaSCN, 6 M guanidine hydrochloride). This activity resided in serum IgG as shown by the following evidence: (1) recovery in the 160 K region after AcA 44 filtration, (2) association with the IgG fraction after purification by DEAE chromatography and AcA 34 filtration, (3) after immunopurification on beta 2m-Sepharose immunosorbent, the labeled eluted fraction was shown to bind to beta 2m-Sepharose and to protein A or anti-IgG-Sepharose. Pepsin-digested F(ab')2 fragments from serum IgG were treated by 3 M urea, then passed on beta 2m-Sepharose immunosorbent in order to prepare specific anti-beta 2m F(ab')2. Those fragments retained all the beta 2m binding capacity of the IgG fraction. Saturation analysis studies showed estimated K values between 1.5 and 9.5 X 10(9) L/M, depending on the preparation it was concluded that normal human serum contains minute amounts of auto-antibodies of relatively high affinities, specific for beta 2m.

Adult↗