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

Tumorigenic and metastasizing activities (TGA; MA) and susceptibility, or resistance to H2O2 and PGE-releasing activity (H2O2R + PGEs+ phenotype) have been examined in 6 Syrian hamster embryo cell strains transformed in vitro with Rous sarcoma viruses (Schmidt-Ruppin and Prague strains). Early observations of extremely high level of TGA and even MA of RSV-SR-transformants never selected in vivo have been confirmed. The correspondence of these properties with a high level of expression of H2O2R + PGEs+ phenotype and its clustering character were demonstrated in 4 RSV-SR transformants, while significantly lower expression of all these characteristics, including TGA, was observed in 2 RSV-Prague transformants. High level of spontaneous MA was noticed in some RSV-SR transformants. A tumor cell line induced in vivo by RSV-SR did not differ from the cell strain transformed in vitro by RSV-SR. Inhibition of H2O2R + PGEs+ phenotype in one of RSV-SR transformants was obtained with non-toxic doses of BCNU and indomethacin, leading to a marked decrease of TGA.
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PMID:Clustering of discrete cell properties essential for tumorigenicity and metastasis. II. Studies of Syrian hamster embryo fibroblasts transformed by Rous sarcoma virus. 255 9

Hodgkin's disease (HD) is considered as a tumor of the lymph nodes histologically characterized by a variety of cell types, resembling a nonspecific inflammatory reaction. The Reed-Sternberg cells present in the granuloma are considered neoplastic due to cytogenetic alterations, tissue culture properties and heterotransplantability. They originate from a macrophage-derived interdigitating reticulum cell. The lymph node is an immunologic organ and its alterations reveal qualitative and/or quantitative defects of the immune system. These are observed in HD at very early stages even with a minimum of lymph node involvement. Considering HD as a neoplasm of the monocyte-macrophage system, our objective was to investigate the functional capability of peripheral blood monocytes transformed into macrophages in vitro. The phagocytic and lytic activities were evaluated by the generation of toxic oxygen metabolites as due to an excessive production of PGE-2. This defect could be corrected by cyclo-oxygenase inhibitors. The defect was present at very early stages of HD and persisted even during prolonged continuous complete remissions. We also found a defect in the ingestion of candida which could not be modified by drug treatment, indicating the existence of a global dysfunction of the phagocyte. Presently, more than 90% of HD patients respond to specific therapy and remain in prolonged remission, being considered "cured". This fact may contribute to the diminished number of reports in relation to the biology of the monocyte-macrophage system in this disease.
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PMID:[The monocyte-macrophage system in Hodgkin's disease]. 264 Apr 76

We have shown previously that the spleens of mice bearing large M-1 fibrosarcomas contain inducer cells which secrete dialysable factors which activate suppressor T cells from unprimed, normal precursor spleen cells. Once activated, the suppressor cells inhibit the in vitro antibody synthesis of cocultured syngeneic splenocytes stimulated by T cell dependent antigens. In this paper we have examined the possibility that prostaglandins are involved in the activation process. Inducer and precursor cells were cultured in Marbrook vessels in chambers separated by dialysis membranes. Using this procedure, suppressor cells were activated following 12 h of culture but were not detectable after 6 h. The cyclooxygenase inhibitors, indomethacin, acetyl salicylic acid (ASA), and ibuprofen all prevented the activation of suppressor cells in a dose dependent manner. Prostaglandin (PG) E1, but not PGF2a or PGD2, restored the activation of suppressor cells in cultures containing the cyclooxygenase inhibitors. Restoration of suppressor cell activation was seen with 1 X 10(-7) M PGE1 but no activation of suppressor cells was seen in control cultures containing up to 1 X 10(-5) M PGE1. In addition, cultured spleen cells from tumor-bearing mice did not secrete higher quantities of PGE than did cells from age and sex matched normal mice. These data suggest that PGE has a modulatory rather than a direct role in the activation of suppressor cells by inducer factors from tumor-activated inducer cells.
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PMID:Activation of suppressor cells by low molecular weight factors secreted by spleen cells of tumor-bearing mice: modulatory role of prostaglandins. 294 Jan 93

Tumor-promoting phorbol esters are believed to affect cell functions by activating a Ca+2- and lipid-dependent protein kinase (protein kinase C). Since such protein kinases may be involved in ovarian granulosa cell metabolism, the effects of phorbol esters on prostaglandin (PG) and progesterone (P) accumulation were investigated. Cells were obtained from immature (28-29 days old) rats 48 h after injection of 20 IU PMSG and incubated for up to 5 h. A tumor-promoting phorbol ester, 12-O-tetradecanoyl-phorbol 13-acetate (TPA), at a concentration of 25 ng/ml, caused 4-fold increases in PGE and 6-keto-PGF1 alpha accumulation at 5 h. LH (10 ng/ml) caused 7- and 4-fold increases in PGE and 6-keto-PGF1 alpha accumulation, respectively. When tested in combination, the increases in PGE and 6-keto PGF1 alpha due to TPA and LH were additive. Like the effect of LH, the TPA stimulation of PG synthesis occurred after a delay of 2-3 h. By 5 h of incubation, cells exposed to TPA exhibited increased PG synthase activity in whole homogenates. TPA caused a smaller (2-fold) increase in P accumulation than was observed with LH (10-fold). When tested in combination, however, TPA decreased the P response to LH by approximately 25%. These effects of TPA on basal and LH-stimulated PG and P accumulation were very similar to the actions of GnRH. We, therefore, investigated the effect of exposure to the combination of GnRH and TPA. A GnRH agonist, [D-Ala6,des-Gly-NH2(10)] GnRH ethylamide (GnRHa; 10 ng/ml) caused a 4-fold increase in PGE accumulation. The effect of TPA on PGE accumulation was also additive to that of GnRHa. TPA, on the other hand, did not affect the 2.5-fold P response to GnRHa. Neither stimulation or inhibition of PGE or P accumulation was observed in the presence of a nontumor-promoting phorbol ester. Furthermore, TPA did not affect basal or LH-stimulated cAMP accumulation or basal or LH-stimulated protein kinase A activity. These data indicate that protein kinase C activation can influence granulosa cell PG and P accumulation.
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PMID:Phorbol ester regulation of rat granulosa cell prostaglandin and progesterone accumulation. 298 45

Purified macrophage interleukin 1 (IL 1) induced a concentration-dependent inhibition of the proliferation of two commonly used tumor cell target lines, the human myeloid K562 and the murine T lymphoma Eb. In contrast, mastocytoma-derived P815 cells were not inhibited. The cytostatic action of IL 1 was not associated with direct cytotoxicity and was only partially reversible. PGE or interferon did not appear to mediate these effects. IL 1 treatment of the multipotential K562 cells revealed no morphologic evidence for the induction of specific differentiation. FACS analysis of IL 1-treated K562 cells showed a rapid decrease in transferrin receptor density, and a more delayed, but highly significant, increase in HLA-A,B,C antigen density. These findings provide one explanation for the frequently reported macrophage cytostatic actions against tumor cells, and indicate as well that IL 1, like interferon, may enhance the expression of Class I MHC antigens. These observations further extend the range of IL 1 actions and underscore the fundamental and direct role of this monokine in macrophage antitumor activity.
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PMID:Macrophage cytotoxicity: interleukin 1 as a mediator of tumor cytostasis. 299 48

A case of mesoblastic nephroma, hypercalcemia, and raised levels of prostaglandins in a 2-month-old female infant is reported. Plasma parathyroid hormone (PTH) was normal and urinary prostaglandins were raised. During surgery a prostaglandin arteriovenous gradient was demonstrated. A large quantity of PGE was extracted from the tumor by radioimmunoassay after incubation. Both blood calcium and urinary prostaglandins returned to normal after nephrectomy. These results show that this tumor produced prostaglandins, the mediators of hypercalcemia in this patient.
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PMID:Congenital mesoblastic nephroma with hypercalcemia. Pathogenetic role of prostaglandins. 301 43

The effect of topical application of PGE on induction of ODC in mouse epidermis was measured. When direct induction of ODC by TPA was blocked by also applying indomethacin, maximum ODC activity occurred only when PGE was applied simultaneously with TPA 4 1/2 hr before killing of the mice. If either TPA or PGE was applied at other times, ODC activity decreased substantially. Induction of ODC by mezerein was blocked by indomethacin but restored by PGE, as was observed with TPA, but induction by ethyl phenylpropiolate was not affected by indomethacin or PGE. DMBA did not cause a consistent increase in ODC activity, nor was its inductive action affected by indomethacin or PGE. However, another weak inducer, acetic acid, exhibited elevated ODC activity when PGE was also applied. Inhibition by topical retinoic acid of ODC induction by TPA was partially overcome in a dose-response fashion by PGE. The results indicate that at least 2 events, elevation of PGE and another independent event, are required for induction of ODC activity. It appears that TPA causes at least 4 independent events essential for tumor promotion. A model for the events in the 2-stage tumor promotion model is proposed.
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PMID:The role of prostaglandin E1 in ornithine decarboxylase induction by tumor promoters. 308 53

To elucidate the mechanisms of stimulatory actions of GnRH on rat granulosa cells (GC), we have compared the actions of a GnRH agonist with those of a tumor-promoting phorbol ester, 12-0-tetradecanoylphorbol 13-acetate (TPA) and Ca+2 ionophore, A23187. GC were obtained from immature (28-29 days old) rats 48 h after injection of 20 IU PMSG. Following prelabeling with 3[H]arachidonic acid (AA), the cells were incubated with the test substances for 10 min and AA release determined. A GnRH agonist, [D-Ala6, des-Gly-NH2(10)] GnRH ethylamide (GnRHa; 10 ng/ml) increased AA release 175% compared to the control value. AA release in the presence of GnRHa was larger than that due to 1 microM A23187 or 40 nM TPA alone. A23187 or TPA increased GnRHa-stimulated AA release further. GC were incubated with the test substances for longer time periods, i.e., up to 5 h. GnRHa caused a 4-fold increase in prostaglandin (PG) synthase activity at 5 h. GnRHa increased PGE accumulation to the same extent as TPA, but only increased PG synthase activity about half as much. In combination with TPA, GnRHa had no influence on TPA-stimulated PG synthase activity, but increased PGE accumulation to levels comparable to those with A23187 plus TPA. GnRHa caused a 2.5 fold increase in progesterone (P) accumulation, which was the same as TPA. P accumulation in the presence of GnRHa was affected by neither A23187 nor TPA. These data indicate that the combination of TPA and A23187 can substitute for GnRH action on PGE and P accumulation in rat GC.
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PMID:Mechanisms of action of gonadotropin releasing hormone on rat granulosa cells. 309 4

The metastatic murine mammary tumor cell line 410.4 and its nonmetastatic counterpart tumor line 410 were examined for the presence of prostaglandin E2 (PGE2) binding using a 3H-PGE2 ligand binding assay. Inhibition of endogenous prostaglandin synthesis with indomethacin was shown to increase markedly binding of 3H-PGE2. Equilibrium binding data for tumor 410.4 show that specific binding is saturable, reversible by unlabeled PGE2, temperature-dependent and specific. PGE1, PGE2 or 16-16-dimethyl PGE2 compete well with 3H-PGE2 for binding. PGD2 partially inhibits 3H-PGE2 binding, whereas PGA2 does not compete. Scatchard analysis of equilibrium binding data reveals a high affinity (Kd = 3.9 X 10(-9) M) and an average of 33,785 binding sites/cell. In contrast, binding of 3H-PGE2 to nonmetastatic line 410 has a slightly lower affinity (Kd = 8.8 X 10(-9) M) and an average of 368,857 binding sites/cell. 3H-PGE binding to line 410 cells is comparatively nonspecific as PGD2 is nearly as effective as PGE1, PGE2 and an analogue of PGE2 in competing with 3H-PGE2 and PGA2 also inhibits 3H-PGE2 binding.
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PMID:Heterogeneity of prostaglandin E2 binding in murine mammary tumor cells differing in metastatic potential. 342 34

This report describes the authors' initial experience with percutaneous gastrostomy (PG) and gastroenterostomy (PGE) in 40 patients. Indications for PG and PGE included alimentation (35 patients) and small bowel decompression (five). Seldinger technique with air distension of the stomach via a nasogastric tube (20 patients) is a simple method to insert small (7-9 French) and firm catheters; tube exchanges for larger and softer catheters often are necessary by this method (23 procedures in 17 patients). Coaxial trocar technique (19 patients) permits initial insertion of softer and often larger catheters (9-14 French feeding tubes), which are less likely to clog or require exchange; the intragastric balloon support method facilitates trocar insertion. Now preferred is a system that uses 18-gauge needle puncture and allows coaxial insertion of a final soft feeding tube at the initial procedure. Small bowel catheter positioning (PGE) (31 patients) was more common than gastrostomy alone (8 patients); "downhill puncture" toward the gastric antrum assists direct guide-wire cannulation of the duodenum via the gastric puncture (12 patients). Five complications occurred; two were major and included catheter dislodgement in one patient. Another patient, who had a pharyngeal tumor, suffered profound respiratory difficulty from premedication and nasogastric tube malposition; patients with head and neck tumors present particular problems with nasogastric tube passage and airway monitoring. Inability to pass a nasogastric tube does not preclude PG and PGE, as direct puncture of the stomach is feasible.
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PMID:Percutaneous gastrostomy and gastroenterostomy: 2. Clinical experience. 348 75


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