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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Suppressor cells from syngeneic P815 mastocytoma-bearing DBA/2 mice that inhibit in vitro generation of specific anti-tumor cytotoxicity were characterized. Suppressive activity was almost completely eliminated by treating suppressive spleen cells with anti-theta serum and complement. Treatment with anti-mouse lg serum and complement or with carbonyl iron did not affect their suppressive activity. When suppressive thymocytes from P815 tumor-bearing DBA/2 mice were tested for their capacity to inhibit the generation of cytotoxicity against L1210 cells, a leukemia line in DBa/2 mice, they did not affect the activity, indicating that the supressor cells in the thymocytes of P815 tumor-bearing mice are specific to the tumor. When Ficoll-Hypaque density cell separation was carried out with cytotoxic spleen cells and suppressive spleen cells from 815 tumor-bearing mice, the dense fraction was enriched for kiler cells whereas the suppressive activitty was mainly recovered in the light fraction. Therefore, killer cells and suppressor cells in P815 tumor-bearing mice are thought to be distinct populations.
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PMID:Characterization of suppressor cells in mice bearing syngeneic mastocytoma. 6 23

Since the humoral immune response has been shown to be associated with immunological enhancement of tumor growth, the study of surface immunoglobulin-bearing cells and plasma cell antigen (PCA)-bearing cells during neoplastic development may provide new approaches to the study of tumor immunology. Peripheral blood was collected every other day from normal and carcinoma-bearing mice. Lymphocytes obtained by Ficoll-Hypaque density centrifugation were assayed for immunoglobulin-bearing cells and PCA-bearing cells using either fluorescein-conjugated goat anti-mouse immunoglobulin or rabbit anti-mouse plasma cell serum and fluorescein-conjugated goat anti-rabbit immunoglobulin. A marked increase in immunoglobulin-bearing cells from tumor-bearing mice was observed by Day 6 and peaked at Day 10. An increase in PCA-bearing cells followed the immunoglobulin-bearing cells increas by 2 to 4 days. The immunoglobulin-bearing cells declined by Day 12, whereas PCA-bearing cells remained elevated through Day 20. Using rabbit anti-mouse plasma cell serum as an immunosuppressive agent, a 4-day prolongation of the mean survival time was observed in rabbit anti-mouse plasma cell serum-treated tumor-bearing mice. This suggests that tumor growth in this model may be related to an active humoral immune response and that suppression of the plasma cell population may prove to be beneficial in the treatment of certain tumors.
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PMID:Relationship of surface immunoglobulin-bearing cells, plasma cells, and tumor development in anaplastic carcinoma-bearing A/J mice. 30 Feb 78

This study was designed to elucidate the mechanism of the leukocyte adherence inhibition (LAI) test in man. To identify the reactive cell types, enriched leukocyte populations (dextran-separated leukocytes and Hypaque-Ficoll-isolated mononuclear cells and neutrophils, as well as rosette-isolated B- and T-lymphocytes) were tested for leukocyte adherence in the absence of serum to tumor-specific antigens. LAI reactivity was not restricted to any of the enriched populations, suggesting the involvement of multiple cell types. Attempts to demonstrate soluble lymphocyte factors in the LAI mechanism have been uniformly negative. In contrast, factors in serum of immune donors were able to arm naive cells to be specifically responsive. This suggests a role for serum factors in the mechanism of LAI reactivity and partially explains the participation of multiple cell types in the responses observed. In additional studies, we could not document a correlation between the magnitude of the dermal test (delayed cutaneous hypersensitivity) and the magnitude of the LAI response in patients with squamous cell carcinoma of the head and neck. In 34 of 54 of these patients, there was agreement between the two tests (both positive, 27 of 54; both negative, 7 of 54). In the remaining 20 patients, the dermal test was greater than 5 mm while the LAI test was negative (less than 30% inhibition).
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PMID:Assessment of the mechanism of the leukocyte adherence inhibition test. 36 86

Brain hemorrhage from an intracranial tumor was encountered in 7 males and 6 females during a 4-year period. In 5 patients, hemorrhage was responsible for the first signs of a previously unsuspected neoplasm. The intracranial lesion was demonstrated by computed tomography (CT scanning) in each patient. Characteristic CT scan findings included: a neoplastic core (high or low density); small, multifocal clots usually at the margin of the tumor; and, surrounding, often extensive, edema. Enhancement of the tumor tissue with intravenous injection of 60% Hypaque was observed in the 8 patients so studied. The regions which were enhanced had a peripheral distribution corresponding to the site of hemorrhage. Microscopic examination demonstrated 7 glioblastoma multiforme, 1 oligodendroglioma, 4 metastatic carcinomas (including 1 each of bronchogenic carcinoma, melanoma, hypernephroma, and adrenal carcinoma), and 1 hemangiopericytoma. High-grade malignancy and extensive, abnormal vascularity appeared to be predisposing factors.
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PMID:Brain hemorrhage from intracranial tumor. 46 14

The feasibility and toxicity of intrathecal lymphoid cell infusions in patients with glioma were examined in this study. Blood rich in lymphoid cells was obtained using the Haemonetics Model 30 cell separator; the lymphoid cells extracted were further purified on Ficoll-Hypaque gradients. Four patients received a total of eighteen autologous lymphoid cell infusions, with between 1 X 10(6) and 5 X 10(9) lymphoid cells being infused on each occasion. No toxicity was observed, but the CSF glucose declined in 2 patients. In 1 patient examined at autopsy the lymphoid cells appeared to have gained access to the tumor bed as well as to the rest of the subarachnoid space.
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PMID:Clinical studies of intrathecal autologous lymphocyte infusions in patients with malignant glioma: a toxicity study. 58 44

Normal human monocytes were evaluated in an in vitro assay of growth inhibition of tumor cells. Monocytes were isolated from the blood of 6 normal subjects by Ficoll-Hypaque separation and adherence to plastic microtest wells. Cervical carcinoma cells (HeLa) were added to the microwells to result in a ratio of 50 monocytes to one HeLa cell. Cultures were then incubated for 6 to 46 hr. Growth inhibition was evaluated by measuring the uptake of 3H-thymidine over a 4-hr pulse period after 2, 18, or 42 hr of monocyte-HeLa interaction. Inhibition of HeLa growth by monocytes was 23.8% +/- 8.6% over 6 hr, 22.0% +/- 8.9% over 22 hr. and 68.3% +/- 7.5% over 46 hr. Growth inhibition of HeLa cells was confirmed by direct enumeration of HeLa cells at the end of coincubation. Attachment of monocytes to the HeLa cells was confirmed by light and scanning electron micrographs. Granulocytes, lymphocytes, and other cell lines did not comparably inhibit HeLa growth and media replenishment did not ablate the effect. These data demonstrate that normal human monocytes can inhibit the growth of a malignant cell line in vitro in the absence of overt activation procedures.
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PMID:Normal human monocytes inhibit tumor cell growth in vitro. 70 63

Erythroid burst forming units (BFU-E) are proliferative cells present in peripheral blood and bone marrow which may be precursors of the erythroid colony forming cell found in the bone marrow. To examine the possible role of monocyte-macrophages in the modulation of erythropoiesis, the effect of monocytes on peripheral blood BFU-E proliferation in response to erythropoietin was investigated in the plasma clot culture system. Peripheral blood mononuclear cells from normal human donors were separated into four fractions. Fraction-I cells were obtained from the interface of Ficoll-Hypaque gradients (20-30% monocytes; 60-80% lymphocytes); fraction-II cells were fraction-I cells that were nonadherent to plastic (2-10% monocytes; 90-98% lymphocytes); fraction-III cells were obtained by incubation of fraction-II cells with carbonyl iron followed by Ficoll-Hypaque centrifugation (>99% lymphocytes); and fraction-IV cells represented the adherent population of fraction-II cells released from the plastic by lidocaine (>95% monocytes). When cells from these fractions were cultured in the presence of erythropoietin, the number of BFU-E-derived colonies was inversely proportional to the number of monocytes present (r = -0.96, P < 0.001). The suppressive effect of monocytes on BFU-E proliferation was confirmed by admixing autologous purified monocytes (fraction-IV cells) with fraction-III cells. Monocyte concentrations of >/=20% completely suppressed BFU-E activity. Reduction in the number of plated BFU-E by monocyte dilution could not account for these findings: a 15% reduction in the number of fraction-III cells plated resulted in only a 15% reduction in colony formation. These results indicate that monocyte-macrophages may play a significant role in the regulation of erythropoiesis and be involved in the pathogenesis of the hypoproliferative anemias associated with infection and certain neoplasia in which increased monocyte activity and monopoiesis also occur.
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PMID:Cell-cell interaction in erythropoiesis. Role of human monocytes. 71 62

With a modified microcytotoxicity assay, the effects of lymphocytes from normal volunteers and from patients with a variety of solid malignant tumors were tested in vitro against both normal and neoplastic target cells. The study was divided into three sequential time phases in each of which a different method of lymphocyte separation was used. Lymphocytes were separated by a Ludox-polyvinyl-pyrrolidone technique in the first phase, by nylon wool filtration in the second phase, and by a Ficoll-Hypaque technique in the third phase of the study. In the first two phases of the study, lymphocytes from both normal volunteers and cancer patients were frequently toxic on both tumor cells and fibroblasts. In the last phase of the study types of target cells. Cancer patient lymphocytes were more frequently toxic on tumor cells but no more frequently toxic on fibroblasts than were normal lymphocytes. The different results obtained in the last phase of the study cannot be attributed solely to the different method of lymphocyte separation, since other factors, such as better growth status of the target cells and greater facility in performing the assays, might also be responsible. Results of the last phase of the study raise the possibility that both specific and nospecific reactions may contribute to the toxicity observed in this laboratory with cancer patient lymphocytes tested against tumor cells. It has not yet been possible to reduce the level or frequency of the nonspecific reactions to such a degree that the microcytotoxicity assay can be used clinically to document clearly or to follow the putative tumor-specific immunity of individual cancer patients.
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PMID:Effects of human lymphocytes on cultured normal and malignant cells. 80 64

In vitro cell-mediated cytotoxicity (CMC) assays have been carried out in human melanoma system with blood effector lymphocytes on [3H]proline-labeled target cells in a 48-hr microcytotoxicity technique. Three lymphocyte purification procedures (Ficoll:Hypaque gradient, plasma gel sedimentation followed by nylon column incubation, and plasma gel sedimentation followed by separation with nylon powder and glass beads) are compared in parallel experiments for characteristic effector cell composition and cytotoxic potential against target cells of dissimilar histology. The cytotoxicity is defined by the loss of target cell 3H cpm as measured by residual target cell 3H cpm in individual microwell following incubation with lymphocytes. Target cell 3H cpm loss by test lymphocytes is compared with target cell 3H cpm loss by several age and sex matched control lymphocytes (from normal donors and unrelated cancer patients); further comparison between the various control lymphocytes is also made in each assay. As control for target cells, autologous fibroblasts and homologous tumor cells of dissimilar histology are always included in each assay. Specific cytotoxicity is defined as statistically significant and selective destruction of only melanoma cells by the test lymphocytes as compared to the control lymphocytes. Significant but nonselective destruction of 2 or more target cells of unrelated histology is regarded as nonspecific cytotoxicity, while no destruction of any target cells signifies no cytotoxicity. The Ficoll:Hypaque preparations consistently exhibit the highest nonlymphocytic cell contamination (8 to 16%); the nonlymphocytic cells are, almost exclusively, monocytes. They also produce relatively high percentage of thymus independent (B) cells (8 to 15%). The ultimate cell composition of the 2 plasma gel-nylon preparations is essentially identical. In either plasma gel-nylon preparations, the nonlymphocytic contamination is minimal (0 to 4%) and thymus-dependent (T) cell percentage is considerably higher (92 to 99%) with none or few B cells.
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PMID:Variables and specificity of in vitro lymphocyte-mediated cytotoxicity in human melanoma. 119 30

In vitro labeling and gold activation autoradiography were used to determine the [3H]thymidine ([3H]TdR)-labeling indices and DNA synthesis times for C3H/He spontaneous mammary tumors. Three variations of the [3H]TdR, [14C]thymidine ([14C]TdR) double-labeling method, together with double-emulsion autoradiography, were used to determine the DNA synthesis times (TS). Tumors labeled totally in vivo (in vivo-in vivo method) and tumors labeled with [3H]TdR in vivo and subsequently labeled with [14C]TdR in vitro showed similar TS values. DNA synthesis times for tumors determined totally in vitro by double labeling (in vitro-in vitro method) were significantly longer than those observed in vivo; however, identical samples subjected to Hypaque-Ficoll gradient separation after double labeling showed TS's similar to those found in vivo. Furthermore, the interval between [3H]TdR and [14C]TdR administration had no effect on TS estimates in vitro. Gold activation autoradiography was used in the present experiments to reduce autoradiographic exposure times. This method, together with in vitro labeling, permits [3H]TdR labeling index and TS determinations after 6-hr and 7-day exposures, respectively.
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PMID:In vitro labeling and gold activation autoradiography for determination of labeling index and DNA synthesis times of solid tumors. 126 32


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