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

The author studied the remote results of the treatment in 1358 breast cancer patients, 554 of them were operated under ether-nitrogen-oxygen anesthesia and 804--under fluothane-nitrogen-oxygen anesthesia. The patients were subjected only to the Halsted mastectomy. Both groups of patients were identical in age and the degree of tumor spread. It is shown that late results of the treatment in breast cancer patients operated under fluothane narcosis are much better than those under ether narcosis.
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PMID:[Types of anesthesia and the late results of breast cancer treatment]. 59 13

The effects of various structural modifications on the antineoplastic activity of the benzenesulfonylhydrazone of 2-formylpyridine N-oxide have been ascertained in mice bearing either Sarcoma 180 or leukemia L1210. To accomplish this a variety of derivatives substituted at the aldehyde proton, the aryl ring, and the 4 position of the pyridine nucleus were synthesized. Antineoplastic activity was retained when nitro, amino, chloro, bromo, fluoro, and methoxy groups were introduced into either the meta or para positions of the phenyl ring of the parent compound. In addition, substitution of the terminal phenyl group by a pyridine ring or by a bulky aromatic ring such as alpha-naphthyl, beta-naphthyl, or fluorenyl did not abolish the marked antitumor activity expressed by this class of agents. Insertion of a nitro function or a morpholino group in the 4 position of the pyridine nucleus of the benzenesulfonylhydrazone of 2-formylpyridine N-oxide resulted in two potent anticancer agents, while the introduction of a chloro function in the 4 position led to a pronounced decrease in biological activity. Furthermore, the essentiality of the aldehydic proton for tumor-inhibitor activity was demonstrated by the inactivity of two derivatives in which the aldehydic proton was replaced by a methyl group or by an oxygen atom.
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PMID:Relationship between structure and antineoplastic activity of arylsulfonylhydrazones of 2-formylprydine N-oxide. 62 18

Radiation sensitivity of the hamster melanoma AMel 3 was studied in vivo and in vitro. In vitro, a dose-effect curve with the dose Do=155 rd and the extrapolation number 10 was obtained. In consideration of an oxygen enhancement factor of 2.5, the results of in-vivo examination with the quantitative transplantation method did not differ from in-vitro results. In living animals, about 40% of the tumor cells generally are hypoxic. These data do not verify the hypothesis of a particular radiation resistance of melanoma cells.
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PMID:[Radiation sensitivity of the amelanotic hamstermelanoma in vitro and in vivo (author's transl)]. 68 78

The assembled evidence suggests that geometry plays an important role in regulation of cell growth, at least at two levels: (1) For non-transformed individual cells in culture, there may be a continuous range of shapes, from spherical all the way to extremely flat or extended, which correlates with increasing proliferative capacity or increasing ability to respond to serum growth factors. In other words, sensitivity to a variety of mitotic stimulators and growth factors may be modulated by cell conformation. Fully transformed cells appear to lose the modulating effect of shape, and thus are able to proliferate even when spherical. (2) For transformed cells which can grow in three-dimensional populations, the shape of the population itself eventually limits growth. The most likely mechanism is based upon the limiting effects of diffusion gradients of nutrients, oxygen and catabolites which build up across the surface of a three-dimensional population of cells. Tumor cells which are able to make tumour angiogenesis factor (TAF), induce new capillary blood vessels from the host. These vessels penetrate the tumor and permit further rapid growth. In this sense, tumor angiogenesis is a mechanism by which "successful" tumors escape the growth restriction imposed upon three-dimensional cell population by geometry [49].
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PMID:Influence of geometry on control of cell growth. 76 36

The heterogeneous structure of tumors is described and the importance of oxygen is explained and analyzed. Three ways of solving the clinical problems of anoxic tumor cells are today being tried. Hyperbaric oxygen breathing before and during irradiation; using fast neutrons and thirdly the use of improved treatment schemes with low LET (i.e. low alpha-value) radiation. The various methods are described and critically evaluated. Calculations are made with the two-component model of radiation. The improved treatment schemes seem in most cases to work well and to solve the problem. If necessary, for certain radio-resistant tumors the normal treatment might also be supplemented by other methods.
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PMID:Problems and trends in radiotherapeutic treatment of deep-seated tumors. 80 92

The effects of different partial pressures of oxygen on the growth of hamster embryo and hamster tumor cells in culture were studied. Hamster embryo cells grown in medium with calf serum became established as continous cell lines in 1 to 3% O2 but degenerated in 20, 50, or 97% O2. The same cells grown in medium with fetal calf serum became established in 1 to 3 or 20% O2 and degenerated in 50 or 97% O2. Hamster embryo cells grown in medium with fetal calf serum in 20% O2 were less sensitive to O2 toxicity after 119 than after 46 culture days. Treatment of secondary or tertiary cultures of hamster embryo cells grown in medium with calf serum in 20% O2 with chemical carcinogens facilitated their establishment and increased their resistance to O2 toxicity. Cells that developed into established lines and cells that died became heteroploid during the first few weeks of their growth in culture. Lines of carcinogen-treated and untreated cells became tumorigenic in hamsters. Cells from tumors grew permanently in medium with fetal calf or calf serum in 1 to 3 or 20% O2, and were very resistant to higher O2 concentrations. Differences in growth rate and O2 consumption of hamster embryo and hamster tumor cells changed the concentration of O2 calculated to occur at the cell-fluid interface for a given concentration in the gas phase. Such changes may have been partly responsible for the observed differences in O2 toxicity.
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PMID:Oxygen toxicity in normal and neoplastic hamster cells in culture. 81 41

The enzymatic destruction of oxidizing products produced during metabolic reduction of oxygen in the cell (such as singlet oxygen, H2O2 and OH radical) involves the concerted action of superoxide dismutase-which removes O-2 and yields H2O2-and H2O2 removing enzymes such as catalase and glutathione peroxidase. A difference in distribution or ratio of these enzymes in various tissues may result in a different reactivity of oxygen radicals. It was found that in red blood cells superoxide dismutase and catalase are extracted in the same fraction as hemoglobin, while glutathione peroxidase appears to be "loosely" bound to the cellular structure. This suggests that in red blood cells catalase acts in series with superoxide dismutase against bursts of oxygen radicals formed from oxyhemoglobin, while glutathione & peroxidase may protect the cell membrane against low concentrations of H2O2. On the other hand, catalase activity is absent in various types of ascites tumor cells, while glutathione peroxidase and superoxide dismutase are found in the cytoplasm. However, the peroxidase/dismutase ratio is lower than in liver cells, and this may provide an explanation for the higher susceptibility of tumor cells to treatments likely to involve oxygen radicals.
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PMID:Enzyme defense against reactive oxygen derivatives. II. Erythrocytes and tumor cells. 81 6

Asparaginase [EC 3.5.1.1.] of Escherichia coli, an anti-tumor enzyme, was inactivated in a time-dependent fashion by mushroom tyrosinase [EC1.14.18.1.]. The inactivation did not proceed, however, when heat-inactivated tyrosinase was used. Exculusion of the atmospheric oxygen or addition of diethyldithiocarbamate, a copper selective chelating agent, prevented the inactivation. The difference absorption spectrum of tyrosinase-inactivated asparaginase versus intact asparaginase exhibited the appearance of marked absorption peaks at 300 and 350 nm. These results indicate that the tyrosyl residue(s) of asparaginase, which is essential for the activity is enzymatically modified by tyrosianes.
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PMID:Studies of enzyme-catalyzed modification of proteins. I. Tyrosinase-catalyzed modification of asparaginase. 81 77

In a Mayo Clinic prospective study of metastasis from osteogenic sarcoma, so-called prophylactic whole-lung irradiation (a 1,500-rad tumor dose to the whole of both lungs, in divided doses, with oxygen and actinomycin) proved ineffective. 14 patients underwnet an operation for metastatic pulmonary disease. The earlier the excision of a metastatic lesion, the greater the chance of an effective cure. Preoperative irradiation of the bone tumor had no positive effect. The primary lesion should also be excised as soon as possible. Surgical removal of a tumor should be followed by immunotherapy or chemotherapy or both. The rate of reliably "cured" cases could be improved by extensive studies of immunologic reaction before and after surgical intervention.
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PMID:Management of osteogenic sarcoma at the Mayo Clinic. 82 96

The rate of cellular losses of hypoxic respectively euoxic cells of the solid experimental tumor "sarcoma 180" was examined in vivo after irradiations with gamma rays, 15 MeV neutrons, and alpha particles. The tumor cells were labeled in vivo, at first with 125I-UdR and after 50 hours with 131I-UdR. After a further interval of about 20 hours the tumor was irradiated. This method of double labeling makes it possible to determine externally the rates of cellular losses in the labeled zones of tumor cells presenting different partial oxygen pressures. The increase of the rates of cellular losses among the euoxic and hypoxic tumor cells induced by the gamma radiation differs by 2.6; it decreases, however, to 1.5 after injection of nitrofurazone prior to the irradiation. After irradiation with 15 MeV neutrons, a difference of only 1.4 was observed. If the tumors were irradiated internally with alpha particles from the reaction 10B(n,alpha) 7Li, there was no difference between the two rates of cellular losses. As far as the above mentioned kinds of radiation are concerned, the ratios from the increase of the rates of cellular losses induced by radiation are well corresponding to the oxygen enhancement found by other authors during their examinations in vitro.
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PMID:[In-vivo-examinations of the relative radiosensitivity of hypoxic tumor cells (author's transl)]. 84 10


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