Publications by authors named "Piaskowski V"

Adenovirus can establish persistent infections which may reactivate and cause disease in immunocompromised hosts. Lymphocytes have been postulated to serve as a site of adenoviral persistence based upon the ability to isolate adenovirus from tonsils and to detect adenovirus DNA by Southern blot hybridization in peripheral blood mononuclear cells (PBMC). To test this hypothesis, a more sensitive and specific polymerase chain reaction (PCR) assay was developed to detect adenovirus DNA.

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Adenovirus has considerable potential as a gene therapy vector, but recent animal data suggest that transduced cells are destroyed by adenovirus-specific cytotoxic T-lymphocyte (CTL) responses. Therefore, it will be important to develop strategies to evade adenovirus-specific CTL responses in humans. As a first step, an assay was developed to detect and characterize human CTLs directed against adenovirus.

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An adenovirus culture-positive lymphoblastoid cell line was derived from a bone marrow transplant recipient with fatal B-cell lymphoproliferative disease and adenovirus pneumonia. At autopsy, focal areas of the lymphoma infiltrating the patient's lung were positive for adenovirus proteins by immunohistochemical staining. The Epstein-Barr virus-transformed B-cell line Mk, established from pleural fluid cells, contained adenovirus virions in both the nucleus and the cytoplasm by electron microscopy.

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Although cellular immune responses are likely important for recovery from acute adenovirus infection, they have not been studied in humans. As a first step, a sensitive assay for the detection of adenovirus-specific proliferative T cell responses was developed. Peripheral blood mononuclear cells from 29 of 30 healthy adults exhibited specific proliferative responses to adenovirus type 2 antigen.

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Immunological evaluations were performed on 14 pediatric cancer patients who received human recombinant interleukin-2 (rIL-2) as a bolus intravenous infusion every 8 h for 5 consecutive days in a phase I trial. Three-to-four patients were treated at dose levels of 10, 30, 60, and 100 x 10(3) Cetus U/kg. Six of the patients had stage D neuroblastoma; the remainder had other solid tumors or leukemias.

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Kinetic analysis was used to define lytic events in peripheral blood mononuclear cells (PBMC) activated in lymphokine conditioned medium (LCM) and recombinant interleukin-2 (rIL-2). This analysis provided quantitative information on the functional properties of these lymphokine-activated killer (LAK) cells against NK-resistant and NK-sensitive tumor cell lines. The maximum rate of target cell lysis (Vmax) and Km (target cell number resulting in 1/2 Vmax) were determined.

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Amplification of the proto-oncogene MYCN (also known as N-myc) in neuroblastomas has been shown to correlate with both disease stage and prognosis, yet little is known about the DNA structures that carry amplified MYCN genes in neuroblastomas in vivo. We have used DNA irradiation and pulsed-field gel electrophoresis to analyze MYCN amplification structures in eight neuroblastomas from separate patients (four primary tumors and four metastatic lesions exhibiting MYCN amplification). Six of the eight neuroblastomas (three primary tumors and three metastatic lesions) exhibited MYCN DNA irradiation profiles consistent with the presence of circular extrachromosomal DNA amplification structures.

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T cell depletion has decreased the incidence and severity of graft-versus-host disease following transplantation of allogeneic bone marrow. In the treatment of leukemia, decreased GVHD has often been associated with diminished antileukemia or graft-versus-leukemia (GVL) reactivity resulting in higher relapse rates. However, we have not seen a loss of the GVL effect following transplantation of marrow grafts depleted of CD3+ T cells.

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We have used counterflow centrifugal elutriation (CCE) to isolate cell populations for an autologous mixed lymphocyte response (AMLR). Enriched T lymphocyte and monocyte populations were obtained rapidly without the need for cells to first form rosettes with sheep RBC (T cells) or adhere to plastic (monocytes). In 16 separate experiments, peripheral blood (PB) was separated by CCE (9) and/or a plastic adherence and nylon wool column method (9).

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We have studied three round cell sarcomas from pediatric patients in tissue culture to compare the electron microscopic morphology of cells in culture to cells from original biopsy specimens. None of the original tumors displayed distinctive features by light microscopy that would allow classification of a specific tumor type, and electron microscopy was not helpful in identifying specific morphologic features that would allow further classification of tumor types. However, electron microscopy of cells in culture from the three neoplasms revealed distinctive morphologic features that did allow further classification of all three tumors.

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The characteristics of a new neuroblastoma cell line (MC-NB-1) established from the bone marrow of a 2-year-old male are described. Morphologically, the cells appear as flattened and epithelial-like or as small and spherical. Electron microscopy demonstrated microtubules and dense core secretory granules.

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This study demonstrates that short term incubation of blood mononuclear cells (MC) in heterologous sera enhances their natural killer (NK) but not their antibody dependent killer (K) activity, and confirms that NK stimulation is not related to blastogenesis. MC were obtained from healthy donors and incubated with RPMI 1640 supplemented with various serum sources. NK and K activity of incubated vs.

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The frequency of three serologically defined HLA-D region antigens--DR, MB, and MT--was determined in a group of 74 children with non-T, non-B acute lymphocytic leukemia (ALL). Statistically, there were no significant differences in the frequency of any antigen in these ALL patients as compared with a panel of 85 normal controls. However, significant differences in HLA-DR frequencies were observed between patients who relapsed or who remained disease-free during a 30-mo period of chemotherapy.

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To increase our knowledge of the pathogenesis of tumour recurrence, cell membrane phenotypes were determined on bone marrow and extramedullary tumour cells at diagnosis and at relapse in 24 children with lymphoid malignancies. There were 19 patients with acute lymphoblastic leukemia and five with non-Hodgkin's lymphoma. Membrane characteristics used for classification were E-rosetting, T antigen, surface immunoglobulin (sIg) and Ia antigen.

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