Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test strains of EIAV by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed varying electrophoretic mobilities for the respective virion glycoproteins gp90 and gp45. Furthermore, peptide mapping comparisons demonstrated structural variations between the gp90 components of the various strains. In contrast, the respective internal proteins of the virus strains displayed identical electrophoretic mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and, in general, produced identical tryptic peptide maps. The observed differences in glycoprotein electrophoretic mobility and peptide maps were highly reproducible and did not vary with repeated passage of the virus strains in cell culture. Thus, these results demonstrate the occurrence of glycoprotein-specific structural variations during persistent infection by EIAV and support the concept of antigenic variation in this retrovirus. This capacity to alter envelope glycoprotein structure, previously reported for visna virus, may represent an important mechanism of retrovirus persistence in the presence of immune responses by the animal host.
 ...
PMID:Antigenic variation during persistent infection by equine infectious anemia virus, a retrovirus. 620 55

Bovine leukaemia virus (BLV) was found to agglutinate mouse erythrocytes. Under optimal conditions, including the use of neuraminidase-treated erythrocytes, 200 microgram/ml of BLV purified from the supernatant fluid of BLV-infected bat cells had haemagglutinating titres of about 512 units. BLV haemagglutination was drastically affected by pH and temperature; maximum agglutination occurred at pH 6 and 4 degrees C. That the BLV haemagglutinin is a glycoprotein was suggested by the fact that trypsin, potassium periodate or neuraminidase, but not lipid solvents or phospholipase C, significantly reduced the haemagglutinating (HA) activity of purified BLV. Furthermore, purified BLV glycoprotein of mol. wt. 51 000 (gp51) had HA activity. The receptors for BLV on mouse erythrocytes were inactivated by proteolytic enzymes but not by sodium deoxycholate or potassium periodate. Neuraminidase treatment of erythrocytes increase their agglutinability fourfold. Haemagglutination is a relatively sensitive test for detecting BLV glycoprotein because 0.4 microgram/ml of glycoprotein can be detected by this method. The pH and temperature sensitivity of the BLV HA reaction and specificity for mouse erythrocytes distinguish BLV from that of equine infectious anaemia virus and murine leukaemia virus, the other C type retroviruses known to have HA activity.
 ...
PMID:Haemagglutination by bovine leukaemia virus. 627 77

Lectin affinity chromatography procedures were evaluated for the isolation of enveloped virus glycoproteins. The major glycoprotein of equine infectious anemia virus (EIAV) bound to concanavalin A (Con A)-Sepharose through interactions which could not be reversed by alpha-methylglucoside, but elution could be accomplished with buffers containing guanidine hydrochloride or sodium dodecyl sulfate. These denaturants, however, also released about one-half of the Con A protein from the Sepharose matrix. This degradation does not appear to have been recognized previously, as denaturants are frequently employed for the isolation of virus glycoproteins from Con A-Sepharose. In contrast, the virus glycoprotein bound equally well to Sepharose-bound Lens culinaris (lentil) lectin affinity columns and was effectively eluted with buffer containing 0.2 M alpha-methylglucoside. The lentil lectin-Sepharose procedure described is rapid, inexpensive and results in the efficient separation and recovery of EIAV glycoproteins. Thus, lentil lectin-Sepharose can provide a useful alternative to Con A-Sepharose for isolating other high avidity glycoproteins from viral envelopes or cell membranes.
 ...
PMID:Isolation of equine infectious anemia virus glycoproteins. Lectin affinity chromatography procedures for high avidity glycoproteins. 630 79

A new isolate of a murine erythroblastosis-inducing spleen focus-forming virus (Cas SFFV), derived from the wild mouse ecotropic murine leukemia virus Cas-Br-M, was further characterized after the production of a nonproducer cell line. When rescued from the nonproducer cells with a helper murine leukemia virus, the Cas SFFV induced rapid splenic enlargement and focus formation when inoculated into adult NFS/N mice. The Cas SFFV nonproducer cell line was also utilized to compare the envelope-related glycoprotein of Cas SFFV with gp52s from three strains of Friend SFFV. Cas SFFV was found to encode a 50,500-dalton glycoprotein (gp50) distinct in size to the envelope-related glycoproteins of the Friend SFFVs. The Cas SFFV was also compared in RNA blot hybridization studies. The genomic viral RNA of Cas SFFV was found to be slightly larger than two polycythemia-inducing strains of Friend SFFV and markedly larger than the anemia-inducing strain. Further comparisons between the SFFVs were made by examining their transforming capabilities in an in vitro erythroid burst assay. The erythroid bursts induced by Cas SFFV and the anemia-inducing strain of Friend SFFV showed similarities in their erythropoietin requirements. This study supports our recent observations that Cas SFFV is biologically similar to the anemia-inducing strain of Friend SFFV yet biochemically distinct from all Friend SFFVs.
 ...
PMID:Cas spleen focus-forming virus. II. Further biological and biochemical characterization. 631 69

Using purified equine infectious anemia (EIA) virus labeled with 3H-glucosamine or 14C-protein hydrolysate, structural proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. As a result, 2 glycoproteins and 10 proteins with molecular weights (mol wt) ranging from 12,000 to 115,000 daltons were demonstrated. Of 12 structural proteins, 3 proteins, namely a glycoprotein with mol wt of 76,000 (gp76) and 2 proteins with mol wt of 25,000 (p25) and 12,000 (p12), respectively, had distinct antigenic activity from one another in immunodiffusion. Development of antibodies against gp76 and p25 was compared in infected horses. The antibody to gp76 appeared earlier and stronger than to p25 in horses infected with the homologous virus strain. The fraction with glycoproteins was found to have hemagglutinating activity which was inhibited by the serum sample from horses infected with equine infectious anemia virus.
 ...
PMID:Structural proteins of equine infectious anemia virus and their antigenic activity. 632 25

Six patients exhibiting severe pancytopenia or overt leukemia associated with myelofibrosis after chemotherapy for malignant disease have been investigated by immunologic techniques and ultrastructural cytochemistry. Initially, five patients displayed severe thrombocytopenia contrasting with mild neutropenia and anemia. Bone marrow biopsies showed a clear megakaryocytic proliferation and an excess of immature mononuclear cells. The demonstration of peroxidase activities at the ultrastructural level and immunofluorescence labeling with a panel of monoclonal antibodies, including an antiplatelet glycoprotein Ib and an antiglycoprotein IIb-IIIa complex, on blood or marrow cells, permitted identification of otherwise unidentifiable promegakaryoblastic proliferation. In two patients, the use of an immunoperoxidase technique with an antifactor VIII-R-Ag antibody has allowed direct confirmation of this diagnosis on bone marrow sections. This megakaryoblastic proliferation was not pure and was variably associated with blasts of other cell lines (erythroblasts or myeloblasts). Changes in the population of blasts were observed during evolution in two patients. The sixth patient had a mild thrombocytopenia associated with severe neutropenia and anemia. Bone marrow biopsy displayed a myelofibrosis and immature cells, without megakaryocytic proliferation. Ultrastructural study revealed a pure basophil-mast cell proliferation. In conclusion, in five of six patients with secondary acute leukemia associated with myelofibrosis, a proliferation of promegakaryoblasts was demonstrated using both immunofluorescent and ultrastructural cytochemical techniques.
 ...
PMID:Therapy-related leukemia associated with myelofibrosis. Blast cell characterization in six cases. 638 Jul 2

A clone of Trypanosoma brucei brucei (DiTat 1.1) was injected into 32 bovids of various breeds, 11 animals being kept as controls. Five animals, Simmental-Ndama F1 crosses, were extremely sensitive. They showed overt symptoms and one died on day 18 of infection despite treatment with a trypanocidal drug. Seven other animals became ill but recovered progressively and cleared the infection. Twenty animals, of breeds generally considered to be trypanosensitive as well as ones from trypanotolerant breeds, did not show symptoms apart from anaemia and cleared the infection. Putative protective antibody, i.e. directed against exposed determinants on the coat variant-specific glycoprotein, was detected by agglutination, complement-mediated lysis and inhibition of infectivity. All animals showed a primary immune response consisting of IgM whose kinetics and amplitude were indistinguishable between animals of differing sensitivity. The response was long-lasting, whether the animals had been treated or not with a trypanocidal drug 3 weeks after infection, and antibody of IgG1 and IgG2 types were detected in certain sensitive as well as resistant animals after 2 months. Some animals were rechallenged with DiTat 1.1 either 1 year after the primary infection or 6 months after inoculation of irradiated trypanosomes. Peak titres of antibody were lower than was the case following primary infection but higher levels of mercaptoenthanol-resistant antibodies were seen. In no case was there any difference in the response of sensitive or tolerant animals. Our results do not support the idea that resistance of certain bovids to African trypanosomiasis is due to a better protective antibody response.
 ...
PMID:Anti-trypanosome specific immune responses in bovids of differing susceptibility to African trypanosomiasis. 669 34

In patients on regular dialysis treatment, uremic symptoms (anemia, osteopathy, myopathy, neuropathy, and disorders of carbohydrate, fat, and protein metabolism) may be partly due to an accumulation of low molecular weight (MW) proteins (10,000 to 60,000 daltons). We tested this hypothesis using membranes with a higher permeability than conventional Cuprophan membranes. The primary aim of the study was to test the cutoff of various hemofilters (Cuprophan [Highflux], polyamide [FH 20], cellulose acetate [Duoflux], and polyacrylonitrile [Hospal RP 7 + 8 and Asahi PAN]) under in vivo conditions. In addition the effects of hemofiltration on plasma low molecular weight protein concentrations, polyneuropathy, and autonomic insufficiency were also tested in a long-term (six-month) study using the membrane with the highest cutoff and most constant sieving coefficient, i.e., Highflux. Low MW proteins with a defined MW were used as marker substances. Sieving coefficients of beta 2-microglobulin, lysozyme, retinol-binding protein, alpha 1-glycoprotein, alpha 1-antitrypsin, prealbumin, albumin, and transferrin were determined during a four-hour hemofiltration (20 L ultrafiltrate). Proteins were analyzed using an immunodiffusion technique. In the long-term study, motor nerve conduction velocity, the Schellong test, and Valsalva maneuver were tested prior to and three and six months after hemofiltration therapy. Highflux, Duoflux, and FH 202 membranes were permeable to proteins with molecular weights up to 15,000 daltons, and the Highflux module had the most constant sieving coefficient during hemofiltration. In the six-month hemofiltration study with the Highflux filter, plasma beta 2-microglobulin and lysozyme decreased significantly as expected. Parameters of polyneuropathy and autonomic insufficiency were slightly improved.
 ...
PMID:Elimination of low molecular weight proteins during hemofiltration. 681 37

Representative glycoproteins including fetuin, protein A, ovalbumin, alpha 1 acid glycoprotein, and the major glycoprotein of equine infectious anemia virus were labelled with 125I by the chloramine-T or Bolton-Hunter procedure and their binding to immobilized Con A or lentil lectin compared to untreated samples of each glycoprotein. Glycoprotein modification was no greater than one substituted residue per protein molecule. Yet the radioiodinated glycoproteins typically displayed only 0-50% of the lectin binding observed with untreated samples. These results indicate that lectin glycoprotein binding can be markedly altered by minor modifications in protein structure.
 ...
PMID:Effects of common radioiodination procedures on the binding of glycoproteins to immobilized lectins. 683 4

An anemia-inducing substance was isolated from the human placenta and designated placental anemia-inducing factor (PAIF). An amount of 2.8 mg was purified from about 70 total placentas (total wet weight, 42 kg). PAIF caused hemolysis of human erythrocytes in vitro and reduced the number of erythrocytes in rabbits to 80% of that in the control by i.v. administration of 27 micrograms/kg of body weight. PAIF is a glycoprotein with a molecular weight of about 20,000 and containing about 56% sugar. Radioimmunoassay using 125I-labeled PAIF and antiserum revealed a common antigenicity with crude anemia-inducing substance in sera from patients with cancer. No cross-reactions were observed between PAIF and alpha-fetoprotein, carcinoembryonic antigen, Australia antigen, human chorionic gonadotropin, or human placental lactogen. The level of anemia-inducing factor in normal serum was less than 100 ng/ml, whereas 43 of 63 cancer patients (68.3%) had over 100 ng/ml of serum anemia-inducing factor. Anemia-inducing factor assay may provide a means of detection and aid in the treatment of malignant diseases.
 ...
PMID:Purification of an anemia-inducing factor from human placenta and its application to diagnosis of malignant neoplasms. 737 Oct


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>