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

A localized, transplantable testicular tumor of the Fischer rat regularly produces hypercalcemia and increased phosphorus clearance in host animals. Light and electron microscopic examinations of the tumor indicate that it is of Leydig origin. There is no evidence that the tumor secretes any biologically active sex steroids, judges by weights of target tissues, when the tumor is grown in castrated or spayed rats. No radioactive steroid hormone formation in vitro was detected using 1-14C-acetate as a precursor although 14C was incorporated into the "C27" sterol fraction. Mass (micrograms) amounts of sex steroids were not detected after purifying large amounts of tumor extracts. The phytosterols, beta-sitosterol, stigmasterol, campesterol, were tentatively identified in tumor extracts but were also found in other tissues and in tumors not associated with hypercalcemia. Administered in vivo, human chorionic gonadotropin caused an acute rise in serum calcium in 3 to 5 hours in tumor-bearing hypercalcemic rats. Only trophic hormones with luteinizing hormone activity were found to compete with 125I-human chorionic gonadotropin for binding to the tumor homogenate in vitro indicating the tumor possessed luteinizing hormone receptors. When the tumor was transplanted intrasplenically, hypercalcemia did not occur unless adhesions formed, suggesting that the tumor hormone was rapidly metabolized by the liver and was probably of small molecular weight. Secretory granules, usually thought to be associated with peptide hormone secretion, were not detected at the ultrastructure level. Cortisol, conjugated estrogen, and an inhibitor of sterol biosynthesis (AY-9944) were effective in lowering the elevated serum calcium. Definitive identification of the agent causing lethal hypercalcemia has not been accomplished. The available data suggest it is not parathyroid hormone or vitamin D. The Leydig cell origin of the tumor, its response to human chorionic gonadotropin in vivo, the lack of secretory granules at the ultrastructural level, and biologic characteristics, all lead to the speculation that the secretory product of the tumor is a new hormonal substance, possibly a steroid precursor or related substance not previously described or is a known substance of small molecular weight whose calcium-mobilizing properties have not been fully characterized. This transplantable tumor may represent a model for one form of neoplastic hypercalcemia occurring in man and may have important implications in the general area of calcium and phosphorus homeostasis.
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PMID:Hypercalcemia and neoplasia. Biologic, biochemical, and ultrastructural studies of a hypercalcemia-producing Leydig cell tumor of the rat. 5 57

Choroidal malignant melanomas in nine patients were treated with proton beam irradiation at the Harvard Cyclotron Laboratory, Cambridge, Mass. Each patient received five proton beam treatments in eight to ten days, totalling 4,730 to 8,570 rads at the tumor. No complications occurred during the treatment or follow-up period, which, at the time of this writing, ranges from one to 24 months, with an average of 12 months. No further growth of the tumor has been observed in any patient. Different signs of tumor regression have been noted. Resolution of the serous retinal detachments that accompanied some tumors is the earliest finding. Pigment changes over the surface of the tumor and adjacent pigment epithelium is a usual initial tumor response. Fluorescein angiography initially showed decreased leakage of dye; later, destruction of the tumor's vasculature and elimination of fluorescein leakage became evident. Only large choroidal vessels remained patient. Ultrasonography revealed decreased height of the tumors postirradiation, and the radioactive phosphorus (32P) uptake test, repeated in one patient, turned negative on postirradiation measurements.
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PMID:Proton irradiation of choroidal melanomas. Preliminary results. 9 32

Hypercalcemia calls first for supportive measures, eg, adequate hydration, movement or mobilization of the patient to the greatest amount tolerated, and reevaluation of drugs being taken. When immediate lowering of the serum calcium level is not clinically mandatory, oral administration of furosemide, corticosteroid, or phosphorus should be considered. In acute emergencies, saline loading and parenteral furosemide therapy should be tried first, except in a patient with renal failure and congestive heart failure, in whom peritoneal dialysis or hemodialysis should be used instead. Calcitonin can be given for the first 12 to 24 hours to lower serum calcium concentration until a definitive management plan is formulated. Corticosteroid, if not contraindicated, should be started as soon as possible. In severe primary hyperparathyroidism with hypophosphatemia, phosphorus can be given intravenously until oral phosphate therapy can be established. Surgery, of course, should be performed as soon as possible. In most cases of neoplasia, mithramycin given according to a recommended schedule is safe and frequently effective. In desperate cases, additional use of prostaglandin synthesis inhibitors probably now is justified by empirical observations. All of these therapeutic measures are used only to stabilize electrolyte balance so that the primary cause of the hypercalcemia can be treated.
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PMID:Management of hypercalcemia. 15 84

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

The direct comparison of O-alkylglycerol composition in the neutral lipids fractions prepared from human hepatocellular carcinomas with that in corresponding preparations from nonneoplastic liver is reported. Tumor-bearing liver and noncancerous liver specimens were obtained either during surgery or at autopsy. Thirty different tissue specimens obtained from 18 cases were analyzed. Representative samples from each specimen were examined microscopically to confirm the pathological diagnosis. Gas chromatographic analysis of alkylglycerol derivatives showed that hexadecylglycerol, octadecylglycerol, and octadecenylglycerol were the principal components. Compared to the noncancerous liver, hepatocellular carcinomas contained higher proportions of hexadecylglycerol and lower proportions of both C18-glyceryl ethers. Associated with this change was an increase in the proportion of saturated to monoenic alkylglycerols. These abnormalities appeared to be more severe in the necrotic areas of the tumors. Higher concentrations of neutral alkyl glycerolipids and of cholesterol were found in the tumors; no differences between the two groups could be found in the levels of ether-linked phosphoglycerides, triglycerides, and lipid phosphorus.
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PMID:Abnormal distribution of O-alkyl groups in the neutral glycerolipids from human hepatocellular carcinomas. 20 51

Incorporation of phosphorus from [gamma-32P]ATP into protein was catalyzed by specific immunoprecipitates from avian sarcoma virus (ASV)-transformed avian and mammalian cells. This incorporation was observed only when antiserum from tumor-bearing rabbits able to specifically precipitate the ASV sarcoma gene product, p60src, was used to immunoprecipitate antigens from transformed cell lysates. Immunoprecipitates of extracts from normal cells or cells infected with a transformation-defective ASV mutant showed no activity in this assay, nor did any immune complexes formed with normal rabbit serum and any of the cell extracts tested. The expression of the protein kinase activity (ATP:protein phosphotransferase, EC 2.7.1.37) was growth temperature-dependent in cells infected with an ASV mutant temperature-sensitive for the transformation. These results on an enzymatic activity associated with the ASV transforming protein are discussed in terms of protein phosphorylation as a mechanism for viral transformation.
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PMID:Protein kinase activity associated with the avian sarcoma virus src gene product. 20 79

Two patients with Burkitt's lymphoma presented with severe hypercalcemia, a previously unreported complication of this tumor. Roentgenograms and radionuclide scans showed multiple osteolytic lesions in both patients. Plasma parathyroid hormone (PTH) was undetectable during the hypercalcemia phase. Chemotherapy was followed by rapid tumor lysis, hyperphosphatemia, phosphaturia and hypocalcemia. The hypocalcemic phase persisted for two weeks despite rapid normalization of serum phosphorus and renal function. Measurement of urinary cyclic AMP, an index of PTH action, indicated that parathyroid function had been suppressed by the hypercalcemia and remained suppressed for almost one week despite marked hypocalcemia.
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PMID:Hypercalcemia with suppressed parathyroid hormone in Burkitt's lymphoma. 20 38

Neutron-activation method was employed to determine the concentration of magnium, sodium, chlorine, phosphorus and calcium in different bone tumors. In relation to normal skeletal tissue in tumor tissues higher concentrations of chlorine and sodium but lower concentrations of calcium and phosphorus were found. The greatest changes in the macromolecular content were noted in sarcoma tissues. Bone tumors differ reliably one from the other by concentrations or ratios of macroelements concentrations, this fact may be used for the differential diagnosis.
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PMID:[Bone tumor macroelements]. 36 5

Rapidly proliferating tissue incorporates more phosphorus than normal. Thus, following administration of radioactive phosphorus (32P), tumors emit increased amounts of radiation which can be detected. With the proper test technique, a correct diagnosis rate of 96-100% is quoted in the literature. By comparison, between 4 and 20% of all eyes enucleated for suspected malignant melanoma without prior 32P testing contained no neoplasm histologically. The radiation exposure is minimal due to the short half-life of 32P and the low penetration of beta-particles. However, the test usually involves a small operation (conjunctiva and Tenon incision). Testing with gamma rays, however, is not yet wholly satisfactory due to the lack of a suitable gamma-ray detector.
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PMID:[The 32P test in ophthalmology]. 39 93

An elevated pigmented mass of the choroid remained stable for 6 1/2 years and then was documented photographically to have increased in size. The tumor stained on fluorescein angiography, produced a visual field defect, and differentially took up radioactive phosphorus. The eye was enucleated and on histologic examination contained a nevus of the choroid. This case shows that enlargement of a choroidal nevus may occur during adulthood, and suggests that despite newer and more sophisticated diagnostic techniques, large nevi and small melanomas of the choroid may be clinically indistinguishable.
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PMID:Enlargement of a histologically documented choroidal nevus. 44 11


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