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Biomedical subjects

E Wagner

Publications and source records attributed to E Wagner.

At least 235 records · Page 13Linked to original sources
PubMed1990

Receptor-mediated endocytosis of transferrin-polycation conjugates: an efficient way to introduce DNA into hematopoietic cells.

Most current gene transfer methods function satisfactorily in specialized systems involving established cell lines but are often not applicable with nonadherent, primary hematopoietic cells, which are notoriously difficult to transfect. To approach this problem, we have investigated an alternative method of gene transfer, "transferrinfection," in which DNA complexed to transferrin-polycation conjugates is introduced into cells by receptor-mediated endocytosis [Wagner, E., Zenke, M., Cotten, M., Beug, H. & Birnstiel, M. L. (1990) Proc. Natl. Acad. Sci. USA 87, 3410-3414]. We show here that transferrin-polylysine and transferrin-protamine, when complexed to plasmid DNA containing a luciferase reporter gene, is efficiently bound and moved into avian erythroblasts by endocytosis. Successful transfer and expression of the luciferase reporter gene depends on specific interaction of the transferrin-polylysine-DNA complex with the transferrin receptor and occurs in a significant fraction (greater than 95%) of the cells. Gene transfer efficiency by transferrinfection is lower than with an optimized DEAE-dextran transfection method but reaches similar efficiencies when the cells are treated with chloroquine. Because the procedure in the absence of chloroquine is completely nontoxic to cells, a constant expression level of transferred genes may be maintained by repeated additions of transferrin-polylysine-DNA complex. In addition, the usefulness of transferrinfection for gene transfer into primary hematopoietic cells is demonstrated.

Animals↗
PubMed1990

Transferrin-polycation-mediated introduction of DNA into human leukemic cells: stimulation by agents that affect the survival of transfected DNA or modulate transferrin receptor levels.

We have subverted a receptor-mediated endocytosis event to transport genes into human leukemic cells. By coupling the natural iron-delivery protein transferrin to the DNA-binding polycations polylysine or protamine, we have created protein conjugates that bind nucleic acids and carry them into the cell during the normal transferrin cycle [Wagner, E., Zenke, M., Cotten, M., Beug, H. & Birnstiel, M. L. (1990) Proc. Natl. Acad. Sci. USA 87, 3410-3414]. We demonstrate here that this procedure is useful for a human leukemic cell line. We enhanced the rate of gene delivery by (i) increasing the transferrin receptor density through treatment of the cells with the cell-permeable iron chelator desferrioxamine, (ii) interfering with the synthesis of heme with succinyl acetone treatment, or (iii) stimulating the degradation of heme with cobalt chloride treatment. Consistent with gene delivery as an endocytosis event, we show that the subsequent expression in K-562 cells of a gene included in the transported DNA depends upon the cellular presence of the lysosomotropic agent chloroquine. By contrast, monensin blocks "transferrinfection," as does incubation of the cells at 18 degrees C.

Chloroquine↗
PubMed1990

Transferrin-polycation conjugates as carriers for DNA uptake into cells.

We have developed a high-efficiency nucleic acid delivery system that uses receptor-mediated endocytosis to carry DNA macromolecules into cells. We accomplished this by conjugating the iron-transport protein transferrin to polycations that bind nucleic acids. Human transferrin, as well as the chicken homologue conalbumin, has been covalently linked to the small DNA-binding protein protamine or to polylysines of various sizes through a disulfide linkage. These modified transferrin molecules maintain their ability to bind their cognate receptor and to mediate efficient iron transport into the cell. The transferrin-polycation molecules form electrophoretically stable complexes with double-stranded DNA, single-stranded DNA, and modified RNA molecules independent of nucleic acid size (from short oligonucleotides to DNA of 21 kilobase pairs). When complexes of transferrin-polycation and a bacterial plasmid DNA containing the gene for Photinus pyralis luciferase are supplied to eukaryotic cells, high-level expression of the luciferase gene occurs, demonstrating transferrin receptor-mediated endocytosis and expression of the imported DNA. We refer to this delivery system as "transferrinfection."

Animals↗
PubMed1990

Evaluating community-based nutrition programs: assessing the reliability of a survey of grocery store product displays.

A pilot test of a survey of grocery store product displays was conducted to measure the amount of health-education information provided and the proportion of the display devoted to "healthier" products. Inter-rater reliability ranged between 0.73 and 0.78 for the healthiness indices and between 0.30 and 0.67 for the health education measures. Test-retest reliability ranged from 0.44 to 1.0.

Food Labeling↗
PubMed1989

[Spontaneous arteriovenous shunt in chronic arterial occlusive disease of the lower extremities. A nuclear medicine study].

For radionuclide assessment of AV-shunting Tc99m aggregated albumin microspheres were injected into the proximal femoral artery in 10 patients with chronic peripheral OAD and a visualized proximal AV shunt during percutaneous transluminal angioplasty. Isotope activity in the lungs and the afflicted leg was investigated with a computer-linked whole body scanner. 12 patients undergoing the same treatment but without proximal AV shunt and one healthy volunteer served as control group. In this group 6 patients suffered from longtime diabetes. Patients with visualized AV shunts showed a significant higher isotope activity in the lungs than non-diabetics without proximal shunts. To our surprise diabetics without proximal AV fistula proved to have also a significant augmented pulmonary activity. Pathophysiological conditions for the evolution of proximal and peripheral AV shunts in patients with chronic OAD are discussed. The poor response to local clot lyses in patients with radionuclide prove of AV shunts underlines their hemodynamic importance under clinical aspects.

Aged↗
PubMed1988

Massive renal and retroperitoneal hemorrhage in a case of acquired renal cystic disease with atypical epithelial cell proliferation.

We present a case of acquired renal cystic disease in a patient with end-stage renal disease (ESRD) secondary to systemic lupus erythematosus who was dialysis dependent for 5 years. Renal hemorrhage and neoplastic transformation of the cyst epithelium are the two major complications of acquired renal cystic disease, and were present in this patient. The full clinical significance of the acquired renal cystic lesion is still unclear, although the possibility of renal tumors and massive renal and retroperitoneal hemorrhage should be considered in the long-term dialysis population.

Adult↗
PubMed1986

Dirofilaria immitis: diethylcarbamazine-induced anaphylactoid reactions in infected dogs.

The immunopathogenesis of the anaphylactoid Mazzotti reactions has been studied by comparing physiologic and immunologic aspects of diethylcarbamazine-induced shock in Dirofilaria immitis infected dogs with antigen induced anaphylaxis in infected and uninfected controls. Filarial antigen, specific host IgG antibody, and C1 and C3 complement levels were quantitatively measured over time in relation to the levels of histamine and prostaglandin D2 in the blood and changes in mean blood pressure. D. immitis antigen injected into uninfected dogs having no detectable IgG antibody to D. immitis or Toxocara canis produced a rapid drop in blood pressure that paralleled a drop in C1 and C3 levels and an increase in prostaglandin D2. Antigen injected into infected dogs with IgG antibody produced a similar drop in blood pressure and complement and increase in prostaglandin D2 which differed from the uninfected group only in the slower clearance of antigen from the blood. Diethylcarbamazine alone produced no measurable changes in blood pressure or complement in uninfected hosts. Diethylcarbamazine, however, administered into skin test positive infected dogs, produced a temporally slower but quantitatively similar loss in blood pressure, drop in complement, and increase in prostaglandin D2 and histamine to that induced by antigen injection. Complement activation and immune complex formation are initiated by antigen release, and subsequent vasoactive mediator release leads to shock with prostaglandin D2 being quantitatively higher in blood than is histamine.

Airway Resistance↗
PubMed1986

[Incidence of psychiatric symptoms in 4- to 8-year-old children with unintelligible speech].

Twenty-four children between 4 years 5 months and 8 years of age with unintelligible spontaneous speech and at least average nonverbal intelligence were evaluated over a period of several hours. Nine of the children (37%) were found to have a psychiatric disorder, either a disturbance of emotions specific to childhood (ICD code 313) or a hyperkinetic syndrome (ICD code 314). No relationship was found between the presence of such a disorder and the severity of the speech/language disorder.

Affective Symptoms↗