Search PubMed⌕ Search

Biomedical subjects

S K Swanson

Publications and source records attributed to S K Swanson.

26 records · Page 2Linked to original sources
PubMed1984

Thymic stroma in AKR mice: its function and virus production.

This study reports experiments with thymic stromal remnants in AKR mice, a strain with a high natural incidence of thymic lymphoma. A method has been developed in which thymic stromal cells which survive a 4-week culture period, 1 week at 24 degrees C and 3 weeks at 37 degrees C are suitable for grafting. Most thymic lymphocytes die under these conditions. Stromal remnants were studied by culturing and grafting under the kidney capsule of 2-month-old syngeneic mice. Their in vitro morphology and virus production, their ability to reconstitute a new thymus from host progenitors and their eventual lymphoma development was evaluated. The stromal remnants were from: 1- and 3-month-old normal mice; 6-10-month-old normal mice; 21-28-day-old animals treated with the lymphomagenic virus, SL3-3, at 3 days of age. Our data show that thymic stromal function as measured by lymphoid reconstitution of thymic stromal grafts of AKR mice is not impaired with age or by the presence of oncogenic virus. Oncogenic viruses are found in the thymic stroma of old mice and in thymic stroma of young virus-treated mice. Oncogenic viruses are not found in thymic stroma of young normal mice. Lymphoma can develop in the grafted stromal remnants expressing lymphomagenic virus.

Animals↗
PubMed1984

Relationship of leukoplakia to urothelial malignancy.

The records of 108 patients presenting with leukoplakia of the urinary tract during the last 35 years were reviewed to define the natural history of this disease, with emphasis upon its association with urothelial cancer. Of the 108 patients 24 had upper urinary tract, 78 bladder and 10 urethral leukoplakia (1 with renal and bladder involvement, 3 with bladder and urethral involvement, and 1 with ureteral and renal involvement). Presenting complaints were primarily irritative. To date, 41 patients (37 per cent) have had associated carcinoma of the urothelium: 23 (21 per cent) presented with a concomitant or previous carcinoma and 18 of 85 (21 per cent) presenting without a concomitant or previous neoplasm have had documented progression to cancer. These figures support the concept that leukoplakia is a premalignant disease and that patients with this diagnosis deserve careful and frequent followup.

Aged↗
PubMed1984

Several classes of retroviruses are produced by an AKR mouse T lymphoma cell line.

Characterization of the viruses produced by the spontaneous T lymphoma cell line SL3 is presented. Using supernatant fluids or direct co-cultivation of cells, the SL3 cell line was found to produce replication-defective viruses in excess of replication-competent viruses. The replication-competent viruses released were predominantly those negative in the XC plaque assay (XC-); XC+ viruses represented a minor population. However, when the SL3-derived viruses were passed in mouse embryo fibroblasts, XC- viruses were rarely recovered, and XC+ viruses were readily isolated. These viruses were all ecotropic and lymphomagenic. Viruses with dual host range and non-oncogenic ecotropic viruses were not isolated from the lymphoma cells. Two replication-defective viruses from SL3 cells were studied. Both could be rescued by non-oncogenic retroviruses and were then lymphomagenic. One defective virus appeared related to XC+ viruses. In these studies, the XC+ and XC- viruses appeared to represent two different interference classes using separate cell receptors. Taken together, these experiments show that the SL3 T lymphoma cells replicate a variety of viruses most of which are lymphomagenic. Virus replication and/or virus integration may be the means of maintaining the malignant phenotype of these T lymphoma cells.

Animals↗
PubMed1982

Bilateral renal cell carcinoma: influence of synchronous and asynchronous occurrence on patient survival.

Twenty-seven patients with synchronous (19 cases) or asynchronous (8 cases) bilateral renal cell carcinoma were treated and followed for as long as 20 years. Tumor grade and stage generally were more favorable in the former group, which is reflected in the higher surgical intervention rate. Nonsurgical treatment yielded poor results. The 5-year survival rate for patients with synchronous bilateral renal cell carcinoma (77.8 per cent) was significantly higher than that for patients with asynchronous lesions (37.5% per cent). Because of its different presentation and favorable prognosis when treated surgically synchronous bilateral renal cell cancer should be distinguished from the asynchronous form, with its dismal outcome. For the latter cases thorough long-term followup may make early surgical intervention feasible, and thus, improve patient survival.

Adenocarcinoma↗
PubMed1982

Spontaneous leukemia viruses: lymphomagenic ecotropic viruses of AKR mice.

The spontaneous leukemia (SL) viruses are ecotropic lymphomagenic viruses isolated from AKR spontaneous lymphomas. These viruses are produced stably by continuous cell lines from spontaneous lymphomas and by a cell line derived from the bone marrow stroma of an AKR mouse neonatally inoculated with an SL virus. All cell lines cloned from the parent lymphoma cell lines consistently produce SL viruses. These viruses can be passaged in vivo and maintain their leukemogenic properties. Cloned isolates of SL viruses accelerate lymphoma in AKR mice and induce thymic lymphoma in mice of other strains. Thus their lymphomagenic properties are conclusively shown. In a study with the use of a sensitive host range assay, xenotropic and/or dual-host range viruses are consistently found in spontaneous lymphoma and cell lines derived from them. However, viruses able to replicate in mink lung cells are not expressed in SL virus-induced lymphomas or their derived cell lines.

Animals↗