Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activity of cyclic 3':5'-nucleotide phosphodiesterase (PDE) (EC 3.1.4.17) was measured in cultured normal and neoplastic rat mammary epithelium. Total PDE activity in normal cells was 1.6 to 6 times higher than that in tumor cells over a concentration range of 0.01 to 1 mM cyclic adenosine 3':5'-monophosphate. PDE activity was distributed between the low-speed (4000 x g) particulate and supernatant fractions in both cell lines, with the particulate fraction possessing 60 to 70% of the total. Double reciprocal kinetic plots were nonlinear, suggesting the presence of high- and low-affinity PDE activities. Similar, but not identical biphasic curves obtained from both normal and neoplastic cells suggested that at least two different PDE activities were present in a membrane-bound as well as a soluble form. Apparent Michealis constants for the high-affinity enzyme ranged from 2 to 6 muM; the low-affinity enzyme was 1 mM. In the presence of 10 mM caffeine and at a substrate concentration of 1 muM, PDE activity was inhibited 40 and 80% of basal levels in normal and tumor cells, respectively. In general, the membrane-bound enzyme was inhibited to a greater extent than the soluble, regardless of the cell line examined. Although normal cells exhibited higher PDE activities in terms of total specific activity, when soluble activities were compared at low substrate concentrations, the opposite was the case. At a substrate concentration of 0.01 muM, normal cell, low-Km soluble specific activity was 40% less than comparable tumor cell activity. Our results support the contention that PDE is induced by its own substrate, cyclic adenosine 3':5'-monophosphate. In addition, they suggest that the low cyclic adenosine 3':5'-monophosphate steady-state levels characteristic of malignant cells are maintained by a soluble high-affinity isozyme of PDE.
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PMID:Cyclic nucleotide phosphodiesterase activity in normal and neoplastic rat mammary cells grown in monolayer culture. 17 39

A case of a vagal body tumor with a solitary cervical node metastasis is described. There was a remarkable familial association: a biopsy-proven paraganglioma occurred in two members of the patient's family and there was a strong clinical suspicion of a paraganglioma in two others. In a review of the literature, eight patients with metastasizing vagal body tumors and eight patients in whom the vagal body tumor was a component of multicentric presentation of paragangliomas were found. Only one other patient in whom there was a familial occurrence involving a vagal body tumor has been reported. Ultrastructural study of the cervical node metastasis revealed the presence of light and dark chief cells containing scanty, membrane-bound, densecore, neurosecretory-type granules. Atypical granules were noted in a few of the dark cells. Nerve fibers, synaptic vesicles, and sustentacular cells, such as occur in normal paraganglionic tissue, were not observed in this tumor.
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PMID:Vagal body tumor (nonchromaffin paraganglioma, chemodectoma, and carotid body-like tumor) with cervical node metastasis and familial association: ultrastructural study and review. 18 17

Quantitative studies have been performed on the immunogenicity of a membrane-bound antigen of a simian virus 40 (SV40) -induced sarcoma in syngeneic BALB/c mice and of subcellular fractions derived from this tumor. The objectives of the investigation were: a) to develop a quantitative in vivo assay of the tumor-specific transplantation antigen (TSTA) and b) to compare the distribution of histocompatibility antigens, H-2, with that of the SV40 TSTA during several fractionation steps. The immunogenicity of the TSTA-containing fractions was assessed from dose-response curves relating tumor size and the amount of protein used for immunization. After digestion of the tumor cell membranes with a limited amount of papain, H-2 as well as TSTA were present in a soluble form. A single immunization with only 2 microng of the solubilized TSTA reduced the tumor size by 70% compared to that in nonimmunized control animals. The results of several fractionation steps suggest that H-2 and the TSTA are not tightly associated in the solubilized immunogenic material.
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PMID:Quantitative in vivo studies of soluble simian virus 40 tumor-specific transplantation antigens of the mouse. 19 45

mRNA was isolated from cultures of AtT-20/D-16v tumor cells and translated in a mRNA-dependent reticulocyte cell-free system. The corticotropin (ACTH) product was purified by a double-antibody immunoprecipitation procedure using antisera specific for the alpha(1-24) sequence of ACTH. The product is shown by sodium dodecyl sulfate/gel electrophoresis and gel filtration on guanidine-HCl columns to be homogeneous with an apparent molecular weight (Mr) of 28,500. A product with the same molecular weight is synthesized when membrane-bound polysomes from D-16v cells are allowed to complete their nascent chains in a reticulocyte cell-free system. Mr 31,000 ACTH isolated from tumor cells has been separated into three proteins of different apparent Mr:29,000, 32,000, and 34,000. The cell-free product contains the same lysine-, methionine-, and phenylalanine-labeled tryptic peptides as the Mr 29,000 ACTH synthesized in the tumor cells. Tryptic peptide analysis also reveals the presence of the alpha(1-39) sequence in the Mr 28,500 cell-free product and suggests that there is only one copy of this sequence in the Mr 28,500 molecule.
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PMID:Characterization of a common precursor to corticotropin and beta-lipotropin: cell-free synthesis of the precursor and identification of corticotropin peptides in the molecule. 20 Sep 34

A 54-year-old man had a fleshy pink vascularized mass in the superonasal quadrant of the right iris. He had a history of an unchanging pulmonary nodule that was followed up for five years with routine chest roentgenograms. Fluorescein angiography demonstrated early filling of numerous fine blood vessels in the mass and diffuse late staining of the lesion. Results of a transcorneal radioactive phosphorus (32P) uptake test were positive. The clinical diagnosis was tapioca melanoma of the iris, with metastatic tumor as a second possibility. The tumor was excised by iridocyclectomy. Light microscopy revealed nests of tumor cells with oval hyperchromatic nuclei. Fontana stains for melanin were negative as were argentaffin and argyrophil strans. Electron microscopy demonstrated light and dark tumor cells containing numerous membrane-bound electron-dense neurosecretory granules. The diagnosis was iris metastasis from a probable bronchial carcinoid. The patient is alive and well years after excision of the iris mass.
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PMID:Iris metastasis from a bronchial carcinoid tumor. 20 56

Rat and mouse liver mitochondria, when centrifuged in a sucrose density gradient (25--50%, w/w), showed the presence of heavy (H) and light (L) subfractions with buoyant densities 1.185 and 1.170--1.165 g/ml, respectively. Mild treatment with digitonin or EDTA (30 mM) shifted H-subfraction of mitochondria into the lighter zone of the gradient and as a result of this the mitochondria were distributed as a homogenous band with buoyant density 1.170--1.165 g/ml. Mitochondria isolated from both MD hepatoma and Zajdela rat hepatoma were characterized by a homogenous banding with buoyant density 1.160--1.165 g/ml. Regarding to this, the content and patterns of polyribosomes bound to outer membranes of mouse tumor mitochondria were studied. Analysis of polyribosomes as well as the results of RNA polyacrylamide gel electrophoresis indicate that the content of these polyribosomes in tumor mitochondria is less than that in normal liver ones. However, the decrease of cancer cell membrane-bound polyribosomes cannot account for the differences in buoyant densities of mitochondria from normal and tumor tissues.
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PMID:Behavior of mitochondria from normal and tumor cells in isopycnic sucrose gradients. 20 78

The process of glycocalyx formation by the trilaminar membrane was investigated at the subcellular level by use of cultivated cancer cells derived from a human stomach adenocarcinoma. Glycocalyx was apparently synthesized on the characteristic trilaminar membrane of Golgi-derived vesicles which gave rise to cytoplasmic vacuoles which, in turn, fused to form an intracytoplasmic cyst. Characteristic microvilli similar to those of intestinal epithelium extended from the membrane lining the intracytoplasmic cyst. These ultrastructural features agree with earlier histochemical findings in suggesting intestinal metaplasia in the origin of the gastric tumor. The morphologic features of the cancer cells clearly indicated that glycoprotein is first synthesized in the Golgi complex and fully formed mucoprotein then emerges as membrane-bound glycocalyx in the vesicles budding from the Golgi stacks. The glycocalyx layer is an integral part of the external leaflet of the characteristic trilaminar membrane. Abundant deposits of glycocalyx in the intracytoplasmic cyst constituted the ultrastructural basis for a distinctive type of signet ring cell that differed from mucous signet ring cells derived from goblet cells.
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PMID:Deviated formation of intestinal glycocalyx in human stomach cancer cells. Another type of signet ring cell. 20 29

The description is given of the distribution of poly(A)-containing mRNA in different subcellular fractions (nuclei, mitochondria, free- and membrane-bound polyribosomes) from the normal tissues hepatoma MD and chick Rous. The amount of poly(A)-RNA is found to increase in all tumor cell fractions, but free polysomes.
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PMID:[The protein-synthesizing apparatus in chemically- and virus-induced tumors]. 22 38

When horse-radish peroxidase (HPO) was administered iv to Vx2 carcinoma-bearing rabbits, an HPO reaction product was detected in the lumina of blood vessels and the extracellular spaces between tumor cells in the first few minutes after administration. HPO was also seen in vesicles in tumor cells. Fifteen minutes to 1 hour after administration, the HPO reaction product was found mainly in the large membrane-bound vacuoles. Within 6--12 hours, the HPO activity gradually diminished in large membrane-bound vacuoles (lysosomes). In conclusion, exogenous HPO was rapidly incorporated into Vx2 carcinoma cells by pinocytosis, and then pinocytotic vesicles were fused with lysosomes.
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PMID:Cytochemical study on uptake of exogenous peroxidase by Vx2 carcinoma cells transplanted into the rabbit. 28 Jul 9

By means of the reaction of inhibition of leucocytes adhesiveness, suggested by Halliday and his coworkers, the authors examined the immune reactivity of 52 oncological patients and 25 healthy donors. The specific cell activity was observed only in oncological patients, and mainly against the antigen from autologous or histologically identical tumor. In a third of patients under examination blood serum would block the specific cell activity. The intensity of the reaction was enhanced in immunotherapy with FHA activated lymphocytes. The sensitivity of the reaction involved proved to be higher than that of the reaction of lymphocytes migration inhibition by the same antigens.
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PMID:[Leukocyte adhesion suppression reaction for determining the immunological reactivity of oncological patients]. 35 53


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