Search PubMed⌕ Search

Biomedical subjects

W Siegert

Publications and source records attributed to W Siegert.

179 records · Page 10Linked to original sources
PubMed1978

Autoradiographic detection of Epstein-Barr virus (EBV)-associated early antigen in a variety of EBV DNA-containing lymphoblastoid cell lines previously designated as nonproducers.

By using autoradiography combined with 125I-labeled IgG prepared from human sera containing high anti-EA (early antigen) antibody titers, EA has been detected in a low fraction of cells in a variety of EBV DNA-containing cell lines previously designated as negative for this antigen. These positive cell lines are highly inducible for EA following treatment with iododeoxyuridine (IUDR) and also contain multiple copies of the virus genome on average. The correlation between IUDR inducibility and spontaneous expression of EA, in particular, suggests that the ability to express EA in both situations is interrelated.

Antigens, Viral↗
PubMed1977

Separation of the Moloney leukemia virus-determined cell surface antigen (MCSA) from known virion proteins associated with the cell membrane.

Cell membranes of Moloney lymphoma cells (YAC, of strain A origin) were solubilized by NP40. The antigenicity of the solubilized protein fraction was assayed by inhibition of the corresponding cytotoxic reaction against YAC target cells. The Moloney leukemia virus (MLV)-determined cell surface antigen (MCSA) was detected with mouse antisera, produced by the repeated inoculation of heavily irradiated YAC cells into syngeneic mice. Virion proteins gp71, p30, p15, p12 and p10 were identified with goat or rabbit antisera against purified Rauscher and Friend leukemia virus proteins. MCSA was found to bind to Con-A--Sepharose and was eluted by mannoside together with H-2A AND GP71. In contrast, p30, p12, p10 and part of p15 and p15(E), were not retained on the column and could be separated from MCSA. Passage of the glycoprotein fraction through Sephadex G-200 led to the separation of MCSA activity from gp71 and H-2A. MCSA eluted between the immunoglobulin (IgG) and the bovine serum albumin (BSA) size markers. MCSA could be also separated from the known viral proteins and from H-2 by velocity centrifugation in sucrose gradients. It sedimented with approximately 6.6 S ahead of gp71 (4.4 S) and H-2 (3.2 S). It is suggested that MCSA may be a glycoprotein with an approximate molecular weight of 110,000 and distinct from the known viral proteins gp71, p30, p15(E), p12, p10 and from H-2.

Animals↗
PubMed1977

Solubilization of the Epstein-Barr virus-determined nuclear antigen and its characterization as a DNA-binding protein.

The Eptstein-Barr virus (EBV)-determined nuclear antigen (EBNA) was solubilized from isolate nuclei of two EBV-transformed cell lines- Raji and AW-Ramos, by high-salt treatment. Its DNA-binding properties were studied by DNA-cellulose chromatography and a 51Cr release complement fixation assay. EBNA binds to both double-stranded and single-stranded calf thymus DNA, showing a higher affinity to double-stranded DNA. There was no detectable difference in the DNA binding of EBNA prepared from Raji and AW-Ramos cells.

Antigens, Viral↗
PubMed1977

Detection localization of Epstein-Barr virus-associated early antigens in single cells by autoradiography using 125I-labeled antibodies. (With 1 color plate).

A characteristic feature of virus-transformed cells is the expression of virus-specific antigens usually detectable by immunological or radioimmune procedures. We report here an autoradiographic method for the detection and localization of such antigens in individual cells which combines the cellular specificity and radiolabeling sensitivity of the above procedures. As a test system we have studied the reaction between virus antigen in some Epstein-Barr virus (EBV) DNA-containing cell lines and anti-virus antibody specificities in certain human sera. EBV DNA-containing cell lines express an EBV-determined nuclear antigen (EBNA) and some lines also express the EBV-associated antigens, early antigen (EA) and virus capsid antigen (VCA), in a minority of cells in the population. By employing appropriate 125I-IgG-labeled human sera, we clearly show that EA can be detected without difficulty in cell lines known to spontaneously express this antigen. Moreover, the specificity and sensitivity of the present method is such that low levels of EA cand be detected at cellular concentrations which remain undetectable by conventional immunofluorescence.

Animals↗
PubMed1973

Direct evidence for messenger activity of influenza virion RNA.

In a cell-free system of Escherichia coli, RNA from influenza virus particles is translated into a polypeptide antigenically identical with the ribonucleoprotein and several more proteins, some of which correspond in size to viral structural components.

Animals↗
PubMedDate not supplied

Use of amphotericin B aerosols for the prevention of pulmonary aspergillosis.

Invasive pulmonary Aspergillus infections are increasingly recognized among severely neutropenic and/or immunosuppressed individuals. As the infections are usually acquired through the inhalation of Aspergillus conidia, at present prevention of invasive pulmonary aspergillosis consists mainly of the reduction of environmental exposure to aspergillus conidia. More recently, prophylaxis with amphotericin B aerosols has been investigated. Inhalations with amphotericin B aerosols significantly delayed mortality in an animal model of invasive pulmonary aspergillosis and high pulmonary concentrations of amphotericin B could be achieved. In man, pulmonary deposition of amphotericin B could also be demonstrated using commercially available nebulizers. Inhalations were well tolerated with little systemic absorption of the drug. In order to evaluate the efficacy of aerosol amphotericin B administrations for the prevention of invasive pulmonary aspergillosis, a prospective randomized trial has been initiated.

Aerosols↗
PubMedDate not supplied

Rh antibodies against the pretransplant red cells following Rh-incompatible bone marrow transplantation.

A 22-year-old, blood group O, Rh-positive (R2r) man received bone marrow from his blood group A, Rh-negative (rr), HLA-identical sister for treatment of acute lymphocytic leukemia. The patient's pretransplantation serum contained anti-A in a low concentration; therefore, plasmapheresis was not done prior to transfusion of bone marrow. To prevent graft-versus-host disease, bone marrow was incubated with absorbed rabbit antithymocyte globulin prior to infusion, and the patient was treated with methotrexate in the posttransplantation period. After transplantation, the patient received 6 units of group O, Rh-negative (rr) packed red cells from random donors and 6 units of platelets from the marrow donor. Three months after transplantation, 0.5 percent of his red cells were still of the host's type (group O, Rh-positive), as detected by immunofluorescence technique in blood smears. Four months after transplantation, three different Rh antibodies--anti-D, -E, and -G--were detected. Since the patient received only Rh-negative red cell transfusions, it is concluded that he was immunized to his original red cells.

Adult↗
PubMedDate not supplied

Candida dubliniensis candidemia in patients with chemotherapy-induced neutropenia and bone marrow transplantation.

The recently described species Candida dubliniensis has been recovered primarily from superficial oral candidiasis in HIV-infected patients. No clinically documented invasive infections were reported until now in this patient group or in other immunocompromised patients. We report three cases of candidemia due to this newly emerging Candida species in HIV-negative patients with chemotherapy-induced immunosuppression and bone marrow transplantation.

Adult↗
PubMedDate not supplied

Changes in the protein composition of Epstein-Barr Virus-negative lymphoma cells after EBV-conversion.

Two-dimensional protein separation, combining high resolution isoelectric focussing with SDS gel electrophoresis, was applied to analyse Epstein-Barr Virus (EBV)-induced changes in the protein composition of lymphoma cells. Total lysates of the EBV-negative Burkitt lymphoma lines Ramos and BJAB were compared with their permanently converted EBV-genome positive sublines, after 35S-methionine labelling. Five out of seven EBV-infected lines showed a 68k protein, which was absent from both EBV-free parental lines, and was identified as a glycoprotein (gp 68) by metabolic sugar labelling. We conclude that presence of this protein is a direct or indirect consequence of the presence of the EBV genome.

Burkitt Lymphoma↗
PubMedDate not supplied

Treatment of non-hodgkin's lymphoma of low-grade malignancy with human fibroblast interferon.

10 patients with advanced non-Hodgkin's lymphoma of low malignancy were treated with partially purified HulFN-beta. They received daily i.v. infusions of 4.5 X 10(6) IU for 4 weeks, followed by 9 X 10(6) IU daily for 2 weeks. Patients with stable disease during this period received consolidation therapy with 4.5 X 10(6) IU three times per week for a maximum of 20 weeks. Six out of 10 patients had progressive disease after the initial 6 week treatment and 4 had stable disease. Two of the latter developed progressive disease during consolidation therapy, one had a complete remission of minimal bone marrow involvement, and one was in partial remission with a loss of bone marrow infiltration but unchanged lymph node enlargement.

Adult↗