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

Pituitary tumors were induced in F344 female rats by chronic treatment with diethylstilbestrol (DES, 8-10 mg) implanted subcutaneously in silastic capsules. Over a range of 1-150 days of DES treatment, pairs of control and DES-treated rats were sacrificed, and their pituitaries dissociated enzymatically into single-cell preparations. The cell populations were examined regarding total cell recovery correlated with gland weight, intracellular prolactin (PRL) content and subsequent release in primary culture, immunocytochemical PRL staining, density and/or size alterations via separation on Ficoll-Hypaque and by unit gravity sedimentation, and cell cycle analysis, after acriflavine DNA staining, by laser flow cytometry. Total cell yields from DES-treated pituitaries increased from 1.3 times control yields at 8 days of treatment to 58.9 times control values by day 150. Intracellular PRL content ranged from 1.9 to 9.4 times control levels, and PRL release in vitro was significantly and consistently higher than controls, after at least 8 days of DES exposure. Beyond 8 days of DES exposure, the immunochemically PRL-positive proportion of cells increased to over 50% of the total population. Increased density and/or size and PRL content were indicated for the majority of the PRL cell population in both types of separation protocols. All these effects of DES were more pronounced among previously ovariectomized animals. The data extend the findings of other investigators, further establishing the DES-induced tumor as a model for study of PRL cellular control mechanisms.
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PMID:Characterization of estrogen-induced adenohypophyseal tumors in the Fischer 344 rat. 688 57

Tumor-associated lymphocytes (TAL) were isolated from ascites ovarian tumors by stepwise application of density and velocity sedimentation on discontinuous Ficoll-Hypaque gradients and fetal bovine serum. TAL had low levels of natural killer (NK) activity compared to levels of peripheral blood lymphocytes (PBL) from the same patients or control subjects. When TAL were mixed with PBL, significant inhibition of NK activity was observed in 7 of 27 patients tested, with the suppression levels ranging from 14 to 60%. Inhibition of PBL NK activity was observed at the ratio of TAL to PBL of 1:1 or 2:1. Suppression of NK activity was detected with effector-to-target cell ratios ranging from 6:1 to 25:1 and at incubation time from 4 to 20 hours in the cytolysis assay. Tumor-associated macrophages from 6 patients were tested for suppression of NK activity. Only with 1 donor was a 17% inhibition observed at a ratio of macrophages of PBL of 1:1. Thus suppression by mature plastic adherent macrophages does not play a major role in the determination of the low levels of NK in human ascites ovarian tumors and the inhibitory activity of suppressor TAL, which had a minor contamination (less than 5%) with mononuclear phagocytes. When TAL from 1 patient with suppressive activity were passed through nylon wool, inhibition of NK activity was observed with both adherent and nonadherent cells.
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PMID:Inhibition of natural killer activity by tumor-associated lymphoid cells from ascites ovarian carcinomas. 694 71

One major issue in studies on natural killer activities centers around the concept of heterogeneity of effector cells in the NK population. In this study Ficoll-Hypaque fractionated PBL from normal adult donors were used as effectors against a variety of tumor targets in in vitro chromium release assays with the goal of substantiation of the existence of NK subsets. Effectors with common or distinct specificities were demonstrated by the cold target inhibition assays as well as by immunoadsorption studies using tumor cell monolayers. In particular, a distinct subset of NK effectors, with the unique ability of killing a myeloma cell line (FRV), hitherto an NK-resistant tumor target, was demonstrated with the PBL of one normal donor (LP). Separation of this unique subpopulation based on differential light scatter property was achieved using flow cytometry (FACS III). The unique FRV killers were larger than the effectors which lyse K562 and they resemble the activated NK cells in the mouse system.
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PMID:Identification of distinct target-specific subsets of NK cells in peripheral blood of normal donors. 704 59

The [3H]proline microcytotoxicity technique has been adopted to examine the spontaneous cytotoxic property of human circulating monocytes (M) derived from the peripheral blood and resident monocytes/macrophages (M0) derived from effusion fluids. A leukocyte fraction is obtained by centrifugation in Ficoll-Hypaque (F-H) gradient. M are then isolated as adherent cells following incubation of the leukocyte fraction in plastic flasks containing 50% fetal calf serum (FCS) in culture medium. M0 are isolated from effusion fluids after first separating the Fc receptor bearing cells (as Fc receptor-7S EA resettes) in F-H gradient and then enriching them as adherent cells. The above techniques yield a M/M0 population of some 90-98% purity. The M/M0 non-selectively lyse tumor cells and allogeneic normal fibroblasts in the 48 h [3H]proline assay. The fibroblasts, however, exhibit considerable resistance to lysis, particularly at lower effector to target ratios. While appreciable levels of cytotoxicity are observed with resident M0 at 6 h, followed by a further increase in the level of cytotoxicity at 24-48 h, circulating M exhibit a consistent level of cytotoxicity only at 24-48 h. When circulating M and resident M0 from the same donor are examined concurrently for cytotoxicity, resident M0 are consistently found to show significantly higher levels of cytotoxicity when compared to circulating M. This may reflect a true functional heterogeneity within this lineage of effector cells or some degree of in vivo activation of resident M0 in malignant and non-malignant effusion fluids. Further studies of spontaneous cytotoxicity by M/M0 through CMC assay techniques, such as the [3H]proline microtoxicity technique, will be useful in the examination of the role of M/M0 in cell mediated immunity and immunosurveillance against cancer.
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PMID:In vitro assay of spontaneous cytotoxicity by human monocytes and macrophages against tumor cells. 745 96

In malignant pleural effusion, lymphocytes (MPEL) and autologous tumor cells (ATC) were obtained by centrifugation on discontinuous density gradients from 16 patients with malignant pleural effusion. The cytotoxicity of MPEL against ATC were compared with that of peripheral blood lymphocytes (PBL). It was demonstrated that the results for separation with 100%: 60% Ficoll-Hypaque which formed a discontinuous density gradients were the best in three sets of discontinuous density gradients. The cytotoxicity of PBL was higher than that of MPEL (P < 0.001), but the cytotoxicity and expansion of MPEL-activated by rIL2 was much higher than that of PBL-activated by rIL2 (LAK cells) (P < 0.001). This shows that local immune reaction within pleural cavity of patients with malignant pleural effusion was in the state of suppression, but the state could be improved by using rIL2. Therefore, we consider that MPEL could be the better effector cells than LAK cells in tumor adoptive immunotherapy.
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PMID:[The cytotoxicity of malignant pleural effusion lymphocytes and LAK cells against autologous tumor cells]. 755 55

Interleukin-6 (IL-6) is a multifunctional cytokine postulated to play a central role as a growth factor for multiple myeloma (MM). We evaluated the spontaneous secretion of IL-6 in supernatants of Ficoll-Hypaque--enriched bone marrow (BM) cultures from 35 patients with MM. The levels of IL-6 were correlated with biological and clinical characteristics of the disease. High levels of IL-6 production defined a subgroup of patients with low tumor burden as determined by lower serum beta 2-microglobulin (B2M) (P = .02) and lower percentage of myeloma cells infiltrating the bone marrow (P = .003), higher synthetic rates of monoclonal protein (P = .006), and low proliferative compartments as measured by the percentage of Ki-67--positive myeloma cells. Patients with high proliferative fractions (Ki-67--positive myeloma cells > 20%) had significantly lower levels of IL-6 when compared with patients with low proliferative fractions (P = .005). Our findings do not support IL-6 as a major growth factor for MM, but demonstrate an association of high levels of IL-6 secretion with low tumor cell burden and low proliferative fraction.
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PMID:High levels of interleukin-6 are associated with low tumor burden and low growth fraction in multiple myeloma. 814 57

When treated with CD3 moAB (aCD3) (1 microgram/ml) and human natural IL-2 (nIL-2) 1000 U/ml, during the exponential phase of growing: 200 U/ml tumor infiltrating lymphocytes (TIL's) from brain tumors could be expanded. Due to the low percentage of lymphocytes in malignant brain tumor tissue (1%) it was not possible to separate the tumor bearing lymphocytes from the tumor cells by a Ficoll Hypaque gradient separation. This resulted in a co-culture of both lymphocytes and tumor cells in which a serum free medium was used. To generate TIL's at all, it was necessary to supplement this culture medium with 20% of the supernatant of cultures of lymphokine--activated killer cells. In 9 out of 12 cases we obtained total growth factors in the range between 10(4) and 10(14) (average 3.6 x 10(7)). These growth were reached after 6 to 13 weeks including up to 3 weeks of an initial lag period during which no cell growth was observed. We noted a decrease in CD8+ cells, whereby the predominant cell type at the end of the cultures was CD3+ and CD4+. The levels of their cytotoxic activities against K-562 and Raji cells were low in contrast to those of CD3 and nIL-2 stimulated cells which were obtained from carcinomas.
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PMID:Tumor infiltrating lymphocytes in malignant brain tumors. 823 6

Natural killer (NK) cells spontaneously lyse a variety of tumor cells in vitro, and are believed to play an important role in host resistance to tumor growth and metastasis in vivo. As part of our work in comparative oncology, we have designed and validated a canine NK cell assay. Of several lymphocyte isolation techniques evaluated, sedimentation of whole blood through a two-step Ficoll/Hypaque gradient (sp. gr. 1.066/1.119) followed by plastic adherence of monocytes resulted in the most pure lymphocyte population (> 95% lymphocytes). Of four cell lines evaluated as targets in the NK assay, a canine thyroid adenocarcinoma (CTAC) cell line was determined to be most sensitive, and a lymphoblastoid (CT45-S) cell line was determined to be most resistant to NK lysis. A 15 h effector-target incubation period using these targets resulted in reproducible measurement of cell specific lytic activity. Passage of canine lymphocytes through nylon wool columns did not result in a significant increase in NK activity. A final sedimentation of purified lymphocytes through a 45/50% Percoll gradient concentrated NK activity into a single band of lymphocytes. Lymphocytes forming conjugates with CTAC target cells were 5.5-6.5 microns in diameter, and were characterized by a reniform nucleus and varying numbers of electron-dense cytoplasmic granules.
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PMID:Measurement of NK activity in effector cells purified from canine peripheral lymphocytes. 843 Apr 95

Prior studies regarding immune function in bile-duct ligated rats have illustrated blunted immune function. The present study measures natural killer (NK) cell activity. Rats underwent bile duct ligation (BDL) or sham celiotomy (SC) and were sacrificed at 1, 2, and 3 weeks after surgery. Ficoll-Hypaque density centrifugation was used to obtain a purified preparation of splenocytes. NK cell activity was determined by incubating varying concentrations of splenocytes with chromium-labelled YAC-1 tumor cells for 4 hours. Chromium release was measured by a gamma counter and expressed as per cent activity (compared with 100 per cent activity obtained by complete lysis with detergent). The experiments were repeated after preincubation in tissue culture flasks to remove an adherent cell population. NK cell activity was decreased at all spleen cell:target cell ratios studies at 1 week after BDL. At 2 weeks after BDL, NK cell activity was decreased at all but the lowest two concentrations; and 3 weeks after BDL, NK cell activity was decreased only at the highest concentrations used. Separation of an adherent cell fraction restored NK cell activity. This suppression in NK cell activity one week after BDL may account, in part, for the poor response of BDL animals to bacterial and immune challenge. Restoration of activity after removal of an adherent cell fraction suggests that macrophages may be at least partly responsible for this inhibition.
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PMID:Suppression of natural killer cell activity in biliary obstruction. 860 Aug 43

Paraduodenal hernia is a rare condition in which the small bowel loops are herniated into an unusual fossa in the periduodenal area. We treated a patient with paraduodenal hernia diagnosed preoperatively. A 28-year-old woman was admitted to our hospital because of intermittent abdominal pain. Abdominal ultrasonography revealed a large tumor adjacent to the pancreas. Provisional diagnosis made according to computed tomography (CT) findings was tumor of the pancreas tail. However, on a CT scan performed after the administration of diatrizoate meglumine/diatrizoate sodium (Gastrografin, Schering, Berlin, Germany) the mass was shown as a jejunum loop located between the stomach and the pancreas body. Subsequent laparotomy revealed that the jejunum loop was herniated into an unusually large mesocolic fossa and that the hernial orifice was covered by the adhesion between the transverse and descending colons. It seemed that the small intestine within the mesocolic fossa was strangulated by this adhesion. The patient's abdominal pain resolved postoperatively. These observations suggest that paraduodenal hernia should be suspected in patients with chronic, atypical abdominal pain, regardless of the findings for small bowel obstruction.
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PMID:Unusual variant of left paraduodenal hernia herniated into the mesocolic fossa leading to jejunal strangulation. 977 41


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