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

Oncogenic osteomalacia is a syndrome in which unexplained osteomalacia remits after resection of a coexisting mesenchymal tumor. We have investigated the mechanism by which a giant cell tumor of bone caused biopsy-proved osteomalacia in a 42-yr-old woman. The biochemical abnormalities were: hypophosphatemia; decreased renal tubular maximum for the reabsorption of phosphate per liter of glomerular filtrate; negative calcium and phosphorus balance; hyperaminoaciduria; and subnormal calcemic response to exogenously administered parathyroid hormone. Malabsorption, hypophosphatasia, fluorosis, and acidosis were excluded as causes of the osteomalacia. Serum 25-hydroxycholecalciferol was normal (27+/-1 ng/ml). However, the serum concentration of 1alpha,25-dihydroxycholecalciferol was low (1.6+/-0.1 ng/100 ml). Oral administration of physiological amounts of 1alpha,25-dihydroxycholecalciferol resulted in resolution of the biochemical abnormalities of the syndrome and healing of the bone pathology. We suggest that tumor-induced inhibition of 1alpha,25-dihydroxycholecalciferol synthesis caused the osteomalacia. The causal role of the tumor was proved by demonstrating that resection was accompanied by roentgenographic evidence of bone healing and maintenance of normal serum phosphorus; renal tubular maximum for the reabsorption of phosphate; calcium and phosphorus balance; aminoaciduria; and calcemic response to exogenous parathyroid hormone.
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PMID:Osteomalacia due to 1alpha,25-dihydroxycholecalciferol deficiency. Association with a giant cell tumor of bone. 90 49

We treated a small series of patients with choroidal malanomas with radioactive cobalt plaques. To assess the effectiveness of radiation, we performed radioactive phosphorus (32P) uptake determinations before and after treatment. The 32P results did not tumor destruction. In five of seven patients with posterior pole melanomas, radiation retinopathy developed after treatment with resultant decrease in vision.
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PMID:Complications of cobalt plaque therapy of choroidal malanomas. 91 Aug 58

Specimens of different intracranial tumors as well as samples of normal brain have been studied for calcium, magnesium, phosphorus, phospholipids and glycosaminoglycans contents. Tumor tissue showed calcium and magnesium concentrations higher than normal tissue. Brain tumors exhibit a decreased phospholipid concentration than normal brain, and its ability to complex divalent cations (specially magnesium) appears impaired. The glycosaminoglycans contents show no correlation with the concentration of calcium but in cases of observable calcification (meningiomas) a preponderance of chondroitin sulfate was observed.
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PMID:Phospholipids and calcification in human intracranial tumors. 92 87

Ammonium chloride-induced metabolic acidosis produces an increase of the phosphorus turnover rate in tumor tissue. The lower blood protein-bound 32P seems to indicate that the high phospholipid turnover observed in tumor may be related to an increased molecular degradation. It seems likely that this phenomenon together with the augmented release of phospholipid-bound calcium may induce important changes in the cell membrane behavior.
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PMID:Changes in phosphorus metabolism during the tumor growth inhibition by metabolic acidosis. 97 99

Three patients with choroidal melanoma have been observed to develop subretinal hemorrhages associated with their ocular examinations. One hemorrhage appears to have been caused by transillumination, while two others have occurred during radioactive phosphorus testing. Histopathology confirms defects in Bruch's membrane through which blood or tumor cells have entered the subretinal space.
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PMID:Iatrogenic breaks in Buuch's membrane in choroidal melanoma. 102 70

In an epidemiological study in the Neubrandenburg district among 316 long-term exposed pesticide workers the incidence of tumors was investigated. There were 30 cases of tumors, of which 11 were lung cancers. The incidence of lung cancers was in contrast to age-specific population twenty times higher. The average exposure against pesticides amounted to 14.1 +/- 4.7 (6-23) years, the latency period between exposition start and tumor manifestation to 17.9 +/- 6.0 (6-23) years. The exposure occurred mainly to the following agents: herbicides, such as derivatives of phenoxyacetic acid (2,4 D and MCPA); insecticides, such as chlorinated hydrocarbons (DDT, HCH and Toxaphen), organic phosphorus compounds (Parathion) and organic nitro derivatives (DNOC) as well as fungicides, such as copper containing and organic synthetic agents. Between 1950 and 1956 some pesticide workers were also exposed to arsenic containing agents. As the workers were exposed to various chemical compounds simultaneously or alternatively, no carcinogenic effect can be determined by specific individual pesticides. The investigations are discussed in detail on the today knowledge about cancer hazards associated with exposure to pesticides, and respective conclusions are drawn for preventive measures.
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PMID:[High incidence of lung cancer in persons with chronic professional exposure to pesticides in agriculture (author's transl)]. 102 29

The loosely bound chromatin proteins of Ehrlich ascites hyperdiploid cells have been prepared by extraction of chromatin with 0.35 M NaCl. Sodium dodecyl sulfate gel electrophoresis of the 0.35 M NaCl-soluble chromatin proteins reveals high heterogeneity with a molecular weight range of 10,000 to 170,000. The 0.35 M NaCl-soluble chromatin proteins contain many components similar to the more tightly bound non-histone chromatin proteins complex with the loosely bound chromatin proteins by gradient dialysis, the inhibitory effect of histones on transcription of DNA in vitro was reduced. The reconstituted complex manifested a level of template activity similar to that of native chromatin as measured in an Ehrlich ascites tumor RNA polymerase reaction. The loosely bound chromatin proteins contain RNA as well as phosphoproteins. Phenol extraction or DNA affinity chromatography of these proteins yielded fractions enhanced 25- to 30-fold in phosphorus which were capable of stimulating DNA-templated RNA synthesis in vitro. The stimulation of transcription from DNA was template-specific, effective only with a DNA template prepared from Ehrlich ascites tumor, but not from rat liver, calf thymus, or chicken erythrocytes. In addition, the stimulatory effect of the specific DNA-binding proteins appears to be RNA polymerase-specific, the stimulation being manifested with Ehrlich ascites tumor nucleoplasmic RNA polymerase and not with Micrococcus luteus RNA polymerase. Thus, the loosely bound chromosomal proteins from Ehrlich ascites tumor contain a fraction that specifically binds to Ehrlich ascites tumor DNA and exhibits a template- and RNA polymerase-specific stimulatory effect on transcription from DNA.
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PMID:Study of the loosely bound non-histone chromatin proteins. Stimulation of deoxyribonucleic acid-templated ribonucleic acid synthesis by a specific deoxyribonucleic acid-binding phosphoprotein fraction. 111 17

A 57-year-old white woman presented with a small malignant melanoma of the choroid in the macular area of the right eye. The lesion failed to produce a visual field defect or to show fluorescence with angiography, but the radioactive phosphorus uptake(P) test was positive. Histologically, the retinal pigment epithelium was intact over the tumor and the sensory retina was normal. This unusual finding was the most likely explanation for the normal visual field. The intact retinal pigment epithelium over this nonfluroescent melanoma suggests that the destruction of the retinal pigment epithelium occurring with most choroidal melanomas may partially explain why these tumors usually demonstrate fluorescence. This case emphasizes the great accuracy of the P test for diagnosing small malignant tumors of the choroid, even before other popular diagnostic modalities indicate the malignancy of the lesion.
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PMID:Nonfluorescent malignant melanoma of the choroid diagnosed with the radioactive phosphorus uptake test. 111 22

A non-histone protein has been isolated from Ehrlich ascites tumor chromatin. The minimum molecular weight of this non-histone protein, estimated by sodium dodecyl sulfate gel electrophoresis and amino acid analysis, is approximately 10 to 11,000. This non-histone protein is acidic, contains 2.7% alkalilabile phosphorus, binds to DNA, and inhibits transcription of DNA in vitro by the homologous RNA polymerase. The per cent inhibition of RNA synthesis is not affected by increasing amounts of RNA polymerase, but is reduced by addition of excess DNA. In the presence of the non-histone protein, incorporation of [gamma-32P]ATP into RNA in the in vitro RNA synthesizing system is inhibited, with no apparent change in the average chain length of the RNA product. Inhibition of RNA synthesis is completely eliminated if the DNA template is allowed to interact with ATP prior to the addition of the non-histone protein. These results indicate that the observed repression of in vitro RNA synthesis is due to the effect of the non-histone protein on the DNA, inhibiting the initiation of RNA chain formation.
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PMID:Inhibition of transcription in vitro by a non-histone protein isolated from Ehrlich ascites tumor chromatin. 119 69

Twenty-nine patients who had undergone enucleation for ocular malignant melanoma were studied. The results of the radioactive phosphorus uptake (32P) tests were correlated with histopathologic observations. There was a positive correlation between the 32P test results and the histologic degree of malignancy. Mixed cell melanomas were more frequent in the patients ranked with higher 32P test results. Spindle cell melanomas occurred more frequently in patients with lower 32P test results. Mitoses per field and degree of malignancy correlated positively with 32P test results when ranked in a masked manner by two ocular pathologists. Tumor volume and clinical factors did not correlate with the 32P test results. While patients with mixed cell melanomas had higher mean 32P test results than those with spindle cell melanomas, a large variance was noted. Because of this the 32P test is unreliable in predicting the histopathology of a tumor in individual cases.
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PMID:Correlation between degree of malignancy and the radioactive phosphorus uptake test in ocular melanomas. 125 74


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