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Query: UMLS:C0006826 (cancer)
 1,092,456 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several new approaches to radiation therapy with radionuclides have been discussed. Iron 55 is selectively utilized in the red cell developmental cycle and in therapeutic doses, can lower marrow and circulating erythrocyte levels with much smaller degrees of effect on other cell lines. A serious complication, noted in animal studies, is the induction of neoplasma, especially osteosarcoma. Selective irradiation of the cell nucleus is possible with 125IUdR. This results in highly efficient cell killing due to the highly concentrated region of ionization. High concentrations of densely ionizing radiation in the malignant cell may also be accomplished with 211At. The use of labeled liposomes is an additional approach to the delivery of intracellular irradiation. None of these approaches is applicable for the practical treatment of human malignancy at the present time. The importance of these approaches is their value as models for future development of methods that can provide highly selective radiation to target sites.
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PMID:Potential future application with therapeutic agents. 48 48

Serum iron, total iron-binding capacity, and percentage saturation of transferrin have classically been used to demonstrate a hypoferremic state; however, these tests may not discriminate between depleted iron stores and conditions associated with defective reticuloendothelial release of iron. Estimation of stainable iron in the bone marrow biopsy specimen is then the most practical way to assess body iron stores. With the availability of a radioimmunoassay procedure for serum ferritin, we undertook a prospective study to determine whether serum ferritin concentrations might replace assessment of the marrow biopsy iron stores as an indicator of hypoferremia. Iron stores were absent from bone marrow biopsy specimens from 104 patients. A good correlation between low serum ferritin levels and absence of iron stores in biopsy specimens was found for 91 patients (87.5%). Thirteen (12.5%) had normal serum ferritin concentrations with absence of biopsy iron. These individuals had hematopoietic malignancies or active hepatic disease, or were receiving iron therapy. In this group, a bone marrow biopsy would still be necessary for evaluation of a hypoferremic state, even though the serum ferritin concentration might be normal.
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PMID:Serum ferritin and bone marrow iron stores. I. Correlation with absence of iron in biopsy specimens. 50 95

Recently developed techniques for the investigation of iron kinetics were used to study the disturbance of iron metabolism in 19 untreated patients with Hodgkin's diseases (HD). The erythroid abnormality in newly diagnosed HD appears to be confined to those patients with systemic symptoms of weight loss, night sweats and fever, and consists of depression of marrow erythroid activity. These patients had a significnatly lower haemoglobin and serum iron concentration and a higher serum ferritin concentration, both when compared to normal subjects and to those patients with HD who lacked systemic symptoms. Ineffective erythropoiesis and red-cell destruction were not significantly increased. The present findings, confirm that HD patients with systemic symptoms have a depression of erythropoiesis, and that in these patients the marrow fails to respond to the stimulus of mild anaemia.
Br J Cancer 1979 Sep
PMID:Erythropoiesis and iron metabolism in Hodgkin's disease. 50 65

Some polynuclear aromatics (PNA) have been found to be potent carcinogens for all tissues and organs of experimental animals that have been exposed to them, but different dose levels are needed for these effects. They have been known for decades to cause cancer at the site of application but also at certain sites distant from the area of contact. Although some hydrocarbons are potent and complete carcinogens, the majority of related hydrocarbons was originally found to be inactive. Since they generally appear together, it was important to know more about their interaction, particularly whether they would synergize, or antagonize. The polycyclic hydrocarbons have been studied by subcutaneous injection, where they prove very potent carcinogens. They are also very active on the skin of mice where they produce cancer on prolonged application. Inhalation studies, require larger doses yielded negative results until particulate matter was introduced which facilitated the development of lung tumors. Although iron oxide dust was used initially, other dusts were also capable of enhancing the response of the tissue to benzo(a)pyrene carcinogenesis. This point is of importance, particularly since the inhalation of PNA in situations of air pollution or coal mining involves particulates, although of a different type. Soot is not a homogenous substance and several factors determine its properties. Soots will lose some of the absorbed chemicals during their residence in air, but they retain their PNAs for long periods of time when they reach the soil. The carcinogenicity of PNAs in the adsorbed state may be completely absent, depending on particle size of the soot and availability of eluting capability of the tissues or cells in contact with the soot. Whenever the carcinogenic polynuclear aromatics can be eluted they will be active in producing cancer if their residence is adequate. There seems to be no reason to assume that a large increase in coal combustion in the future will by necessity lead to greater risks of cancer to the coal miners or the general urban dweller, because activities to be started now can take into consideration the requirements necessary for control of air pollution in mines as well as in cities. If new uses of coal will be developed, it will be a completely different situation, and statements about the carcinogenic risk from coal utilization do not apply there. Although some of the same carcinogenic PNAs are involved in the health hazards from those processes, other carcinogens and also cocarcinogens will be present, and the exposed workers will not have the apparent benefits of adsorption of PNAs on soot.
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PMID:Health effects of coal mining and combustion: carcinogens and cofactors. 54 Jun 18

Iron oxides, particularly hematite, have been suspected for carcinogenic properties based on epidemiological observations and experimental data. This case-control (case-referent) study concerns a worker population with high exposure to dust of iron oxides, particularly hematite, and with some impurities of pentavalent arsenic and other metals. In spite of the high exposure levels no excess of cancer has been observed, either in the respiratory system or at other sites. It is suggested that earlier findings of respiratory cancers as possibly associated with iron oxides exposure might rather be due to other concomitant risk factors.
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PMID:Cancer incidence and exposure to iron oxide dust. 55 21

Radiotracer 67Ga-citrate is used as a tumor-seeking agent in clinical imaging investigations although fundamental reasons for its high uptake in certain malignant lesions remain unexplained. The mechanism by which 67Ga becomes concentrated in tumor cells has been investigated by comparing 67Ga and 59Fe uptake by cultured mouse myeloma cells with particular reference to uptake stimulation by transferrin. Concentrations of human transferrin down to 2 microgram/ml greatly stimulated cellular uptake of both tracers, whereas bovine transferrin proved relatively inactive. The rates of stimulated uptake of both tracers were similar as was their high degree of retention by cells, but their quantitative dependencies on transferrin concentration showed characteristic differences. Pretreatment of human transferrin with saturating amounts of nonradioactive Fe3+ canceled its ability to promote 59Fe uptake, but it had little effect on its promotion of 67Ga uptake. Further increase in the amount of added Fe3+ did cause a progressive depression of 67Ga uptake, but this effect probably relates to the iron distribution in the whole-cell culture system including the fetal calf serum component of cell growth medium. The results suggest that 67Ga and 59Fe reveal different aspects of the interaction of transferrin with cells.
Cancer Res 1977 Oct
PMID:Transferrin promotion of 67Ga and 59Fe uptake by cultured mouse myeloma cells. 56 54

Thirty-eight metal salts were tested for their capacity to enhance transformation of Syrian hamster embryo cells by a simian adenovirus, SA7. All of the metal salts with known carcinogenic potential in animals or mutagenic activity in microbial or mammalian cells increased the SA7 transformation frequency. Metals were classified into three groups according to the concentration necessary to produce significant enhancement. Those showing highest activity (positive at less than 0.05 mM) were the salts of antimony, arsenic, cadmium, chromium, and platinum. The second group (positive from 0.05 to 0.6 mM) included beryllium, cobalt, copper, lead, manganese, mercury, nickel, silver, thallium, and zinc. Iron salts were placed in a third group (only positive at concentrations greater than 0.9 mM). With the exception of ZnCl2 and ZnSO4, enhancement was demonstrated by both a relative increase in the viral transformation frequency and an absolute increase in the number of transformed foci among treated cells. The latter observation and the demonstration of enhancement in the absence of overt cell killing negate the possibility that enhancement resulted from the selection of transformation-sensitive cells.
Cancer Res 1979 Jan
PMID:Enhancement of viral transformation for evaluation of the carcinogenic or mutagenic potential of inorganic metal salts. 57 89

Serum of 70 patients with malignant lymphoma was tested for concentration of ferritin by immunoradiometric assay. Serum of patients with Hodgkin's disease showed an apparently increased ferritin concentration only in the stage III and IV. Concentration of serum ferritin was found normal in patients with chronic lymphocytic leukemia and non-Hodgkin's lymphoma of low malignancy. Among patients with non-Hodgkin's lymphome of high malignancy only one who suffered from advanced immunoblastic sarcoma showed increased concentration of serum ferritin. Patients with elevated concentration of serum ferritin had a decreased level of serum iron and showed also anemia. Their bone marrow reticulum was rich in dyeing iron. These results suggest that hyperferritinemia in patients with advanced Hodgkin's disease is related to a lack of release of iron from reticuloendothelial system.
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PMID:[Serumferritin in patients with malignant lymphomas (author's transl)]. 59 80

Several studies have shown an increased lung cancer mortality among Swedish metal and iron ore miners, as probably caused by exposure to radon and its daughters. An earlier study of zinc-lead miners has been updated. The results show a 16-fold increase in lung cancer mortality. Surprisingly, nonsmokers were more apt to develop lung cancer than smokers, but the induction-latency time was about nine years shorter on the average for the smokers. An explanation for these findings might be that smoking increases the thickness of the mucus layer and therefore protects the bronchial epithelium from alpha radiation, but it also promotes the development of cancer once induced by the radiation.
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PMID:Mining, lung cancer and smoking. 64 66

CF-1 female adult mice were given weekly sc injections of 20 mg symmetrical 1,2-dimethylhydrazine (DMH)-2HCl/kg body weight and killed at various intervals after commencement of the injection. [3H]thymidine (TdR) was given before the animals were killed. The histogenesis of colon neoplasms was investigated by means of autoradiographs prepared from sections of Epon-embedded descending colon, which were stained with periodic acid-Schiff reaction and iron hematoxylin. By 9 weeks after initiation of DMH treatment, the distal 5 cm of the colon became enlarged, the mucosa thickened, and the crypts were elongated and hyperplastic. In the hyperplastic crypts, the number of proliferating cells increased, but the distribution of these cells followed a previously discussed slow cut-off model of Cairnie et al. as for the normal crypts. Differentiation and transformation of epithelial cells occurred, but somewhat aberrantly. Hyperplasia of the crypts occurred diffusely, but neoplastic lesions that began to appear by 9 weeks after the intiial treatment were isolated. An isolated crypt from which a neoplasm developed was first repopulated by what appeared to be altered, undifferentiated "stem" cells. These cells did not differentiate, continued to divide, and eventually upon migration accumulated in the upper part of the crypts, where an earliest identifiable neoplastic lesion was observed. Once such a lesion was formed, it expanded in various directions, depending on the local environments, and formed a polypoid or discoid lesion. The biologic behavior of the neoplasm seemed to be determined by the downward progression of its leading edge. When it penetrated the muscularis mucosae, the neoplasm became highly invasive. In the murine model, the invasive adenocarcinomas were observed by 26 weeks after commencement of DMH treatment.
J Natl Cancer Inst 1978 Jun
PMID:Histogenesis of symmetrical 1,2-dimethylhydrazine-induced neoplasms of the colon in the mouse. 65 Jul 4


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