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

A woman with a T cell lymphoproliferative malignacy and heterozhgosity at the X chromosome-linked locus for glucose-6-phosphate dehydrogenase (G-6PD) isoenzymes was studied to find the clonal origin of her circulating neoplastic T cells. The red blood cells, polymorphonuclear cells, whole mononuclear cells, and T cell-depleted mononuclear cells contained both A and B isoenzymes of G-6-PD. In contrast, the tumor cells, separated by using their capacity to form rosettes with sheep red blood cells, contained only the B isoenzyme of G-6-PD. This observation strongly suggests the monoclonality of this T cell malignancy.
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PMID:Clonal origin of a T cell lymphoproliferative malignancy. 30 47

One hundred and twenty-seven cultured human tumor cell lines produced tumors after sc inoculation of 1-20 million cells into nude mice. They included 56 carcinoma lines, 14 sarcoma lines, and 57 lines from miscellaneous tumors and were all glucose-6-phosphate dehydrogenase type B. Twenty-nine percent of the lines produced tumors of 1 cm3 size within 1 month and 41% in the second month after inoculation. The histopathology correlated with the human tumor of origin in all cases.
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PMID:One hundred and twenty-seven cultured human tumor cell lines producing tumors in nude mice. 32 80

A number of properties of glucose-6-phosphate dehydrogenase from lactating rat mammary gland and R3230AC rat mammary adenocarcinoma are compared. The main electrophoretic forms of the enzyme from these sources are indistinguishable with respect to charge and molecular weight whereas the minor forms show differences in these properties. The subunit molecular weight and steroid inhibition of the enzymes from the lactating gland and tumor are not significantly different. These results are contrasted with similar studies in mice.
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PMID:Glucose-6-phosphate dehydrogenase from lactating rat mammary gland and R3230AC adenocarcinoma. 43 8

The activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and transketolase were studied in the cytoplasmic fractions of transplanted mouse hepatomas differing in their growth rates, and in the liver, spleen and cortical layer of kidneys of tumour carriers and normal mice. It was shown that transplantation of hepatomas changes the activity of the pentose phosphate pathway enzymes in tumour carrier tissues unaffected by neoplasm. Deviations from normalcy were mainly similar to those observed in the hepatomas. The changes in the enzymatic activities were especially well-pronounced in the mice having rapidly growing hepatomas. This may be due to a generalized effect of the tumour on the organism, which is concurrent with malignancy.
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PMID:[Activities of dehydrogenases of the pentose phosphate pathway and transketolase in transplanted mouse hepatomas with different growth rates and in organs of tumor carriers]. 45 18

In most of the cases studied, histo- and cytoenzymochemical values of metabolism in cancer of the mammary gland correlate with the histological type, differentiation level and the degree of the tumor malignancy. As the histological degree of malignancy increases and the level of differentiation of the mammary cancer decreases, the activity of glycolysis and pentous shunt enzymes, lactate dehydrogenase and glucose-6-phosphate dehydrogenase, increases and that of the Krebs cycle enzymes, succinate and malate dehydrogenase, as well as the enzyme of glycerophosphate shuttle mechanism and oxidation of glycerol-L-glycerophosphate dehydrogenase decreases simultaneously. These data suggest that histo- and cytochemical methods of the enzyme activity determinations may be used for the specification of the prognosis and choosing of the auxiliary methods for the therapy of the mammary gland cancer based both on morphology and metabolism of the tumour.
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PMID:[Histo- and cytochemical enzymatic characteristics of breast cancer]. 51 61

(1) Oxygen uptake and lactate production of different strains of ascites tumor cells were assayed after exposure to an extracellular photochemical system known to produce reactive oxygen derivatives. The various cells tested showed differential sensitivity to the treatment, ranging from nearly full inactivation of Ehrlich cells to nearly full resistance of Yoshida cells. (2) Glucose plus succinate added after the treatment reestablished basal oxygen uptake capacity suggesting that the cell membrane was the primary site of damage. This was confirmed by dye-permeabilization and protein leakage in sensitive cells. (3) H2O2 was shown to be the only relevant oxygen derivative in the production of cell damage: catalase was the only externally added agent that protected sensitive cells, and H2O2 (congruent to 10(-3) M) had the same effects as the photochemical treatment. (4) While the absence of catalase is a feature common to all tumors tested, sensitivity to H2O2 appears to be related to cellular levels of glutathione peroxidase and of its subsidiary enzymes glucose-6-phosphate dehydrogenase, glutathione reductase and glutathione synthetase.
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PMID:Differential sensitivity of tumor cells to externally generated hydrogen peroxide. Role of glutathione and related enzymes. 55 3

Inherited medullary thyroid carcinomas contain one form of glucose-6-phosphate dehydrogenase (G6PD) in black female patients who are mosaic in normal tissues for G6PD types A and B. The same individual may have several tumors each containing either G6PD A or G6PD B. The data suggest that the inherited defect is an initial mutation producing multiple clones of defective cells; each tumor then arises as a final mutation in one clone of these cells.
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PMID:Inherited medullary thyroid carcinoma: a final monoclonal mutation in one of multiple clones of susceptible cells. 61 63

The activities of three enzymes of the hexose monophosphate pathway (HMP) were measured in frozen samples of rat cerebral cortex and ethylnitrosourea-induced tumors of the rat nervous system. Results show that in most tumors, adequate amounts of glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and transketolase (TK) were present so as not to be rate-limiting for utilization of the HMP. When enzyme activites were expressed on the basis of fresh weight, TK was increased in most tumors as compared with cerebral cortex; G6PDH and 6PGDH were more variable, showing either higher or lower activities in tumors as compared to control. Tumors in general had a lower protein content than cerebral cortex. When activities were expressed in terms of this protein content, mean values for the dehydrogenases in all groups of tumors were higher than the average value in cortex, indicating that G6PDH and 6PGDH were spared in tumors relative to other proteins. TK activities in tumors, expressed in terms of cytosol protein were lower than or in the same range as cortex. Increased activities of HMP enzymes in some tumors indicated that the potential activity of the HMP in some (but not all) tumors of the nervous system is greater than that of cerebral cortex.
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PMID:Activities of enzymes of the hexose monophosphate pathway in nervous system tumors induced by ethylnitrosourea. 64 60

Succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G6PDH) and lactate dehydrogenase (LDH) activities have been studied using quantitative enzyme histochemical techniques in the epidermis of five patients with solar keratoses and Bowen's disease. 'Non sun-exposed' buttock skin was compared with the skin from the actual lesion and adjacent, clinically normal paralesional skin. SDH activity was significantly increased in the basal layer and decreased in the granular layer in the epidermis of both lesion and paralesional skin, although the total epidermal activities were unchanged when compared to 'non-exposed' buttock skin. G6PDH activity was increased in the granular layer of paralesional epidermis and of lesions. No change in LDH activity was detected. Inclusion of phenazine methosulphate in the reaction mixtures resulted in a three-fold increase in formazan deposition without altering the localization. It is concluded that the quantitative changes and alteration in localization of SDH and G6PDH reported in solar keratoses are accompanied by similar changes in adjacent, clinically normal 'sun-exposed' skin and differ from normal 'non-exposed' skin. It is suggested that these changes may precede the development of the solar keratoses and that these findings may indicate a significant metabolic alteration in the events that lead to neoplasia.
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PMID:A quantitative histochemical study of three oxidative enzymes in solar keratoses and Bowen's disease. 73 May 44

The ratios of some key enzymatic activities of carbohydrate metabolism have been measured in human tumor cytosols. The activities of whole hexokinase (low Km, EC 2.7.1.1 and high Km, EC 2.7.1.2), 6-phosphogluconate dehydrogenase (EC 1.1.1.43), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and glucose-6-phosphate isomerase (EC 5.3.1.9) change according to a biochemical pattern coherent with cell growth requirements. 6-phosphogluconate dehydrogenase activity was in each sample tested higher than glucose-6-phosphate dehydrogenase activity; this indicates that 6-phosphogluconate, a powerful inhibitor of glucose-6-phosphate isomerase, is unlikely to accumulate and inhibit this enzyme and glucose-6-phosphate channelling into glycolysis.
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PMID:6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, glucose-6-phosphate isomerase, and hexokinase activity ratios in some human tumor cytosols. 74 21


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