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

The posterior pelvic compartment, defined as consisting primarily of the rectosigmoid colon and peritoneal-lined cul-de-sac, was evaluated in 104 patients. Tumors and pseudotumors (fluid- and feces-filled loops of bowel) were ultrasonographically analyzed according to: (a) morphology and echo characteristics, and (b) location within either the cul-de-sac or rectosigmoid colon. On routine examination, a striking similarity between pathological processes and pseudotumors was demonstrated; these were diagnosed correctly only by the use of a technique in which the rectosigmoid colon is filled with water. Combined distension of the urinary bladder and rectosigmoid colon also enabled localization and differentiation of abnormalities within the cul-de-sac.
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PMID:Ultrasound evaluation of the posterior pelvic compartment. 47 46

Clinical studies are being carried out to evaluate whether radiation combined with hyperthermia evokes better tumor control than that achieved with radiation alone. Thus far, 54 patients with various superficial cancers have been treated with combination hyperthermia and radiation. The heating methods used have been temperature regulated water bath immersion and radiofrequency inductive heating. Hyperthermia alone has caused significant, though transitory, tumor regression in 10 out of 19 patients. Selective heating of tumor tissues has been achieved in 20 out of 24 lesions following radiofrequency inductive hyperthermia. The overall local tumor control rate after the combined therapy was 78 percent compared to 26 percent after radiation alone.
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PMID:Treatment of superficial cancers by combination hyperthermia and radiation therapy. 47 11

This study was undertaken to explore the effects of chronic low-level cadmium ingestion in Dahl hypertension-resistant (R) and hypertension-sensitive (S) lines of rats. Groups of weanling female R and S rats were given 0 or 1 mg cadmium/1. in drinking water and fed either a low salt (0.4% NaCl) or a high salt (4% NaCl) diet for 28 weeks. Cadmium produced hypertension associated with gross cardiac hypertrophy and mild to moderate renal vascular changes in S, but not in R, rats on a low salt diet. Cadmium enhanced the rate and degree of development of salt-induced hypertension without exacerbating the hypercholesterolemia or renal vascular lesions normally observed in S rats on a high salt diet. Cadmium lowered circulating cholesterol levels in both lines on a low salt diet. Cadmium had no influence on growth, blood urea nitrogen concentration, plasma renin activity, tumor formation, or survivorship in R and S rats on either salt diet. This study indicates that the genetic composition is a critical determinant of the adverse effects of chronic low-level cadmium ingestion in rats. In addition to the experimental implications, these findings may have relevance to the problem of human "essential" hypertension.
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PMID:Effects of cadmium ingestion in rats with opposite genetic predisposition to hypertension. 48 40

Interaction of the naturally-occurring nucleoside, N6-methyl adenosine, with nitrite, a reaction that occurs readily under acidic conditions, results in the formation of a nitrosamine, N6-(methylnitroso) adenosine[m6(NO)Ado]. This nitrosamine was given in the drinking water (1 mM solution) of non-inbred Swiss mice from 3 weeks of age until death. It caused a significant increase in the incidence of primary lung tumors, compared with controls. It also induced reproductive tract tumors in 80% of the exposed females, including mammary tumors in 60% and uterine tumors in 25%. The precursors of m6(NO) Ado, m6Ado and nitrite, did not elevate tumor incidence when given singly, but when administered together resulted in a significant increase in numbers of lung tumors in the males. The nitrosamine base, N6-(methylnitroso)adenine, was found to be a less potent carcinogen than m6(NO)Ado, causing lung tumors only in males and possibly a few mammary tumors in females. These results indicate the in vivo formation of a carcinogen from m6Ado and nitrite, and show that m6(NO)Ado induces neoplasms in the reproductive system of mice, an unusual target for a N-nitroso carcinogen.
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PMID:Induction of reproductive system tumors in mice by N6-(methylnitroso)-adenosine and a tumorigenic effect of its combined precursors. 48 69

A very rare case of the choroid plexus carcinoma of the left lateral ventricle with metastasis to bone was reported. A two-month-old baby was suffering from irritability and vomiting. Her vital signs became progressively worse. On admission she showed an increased head circumference and meningeal irritation signs. An emergency tapping of the right lateral ventricle at the anterior fontanel revealed the bloody csf and an opening pressure of over 700 mm of water. All laboratory findings were negative. Cerebral angiograms showed only an internal hydrocephalus. CT scan and conray-ventriculography gave the finding of a tumor at the trigone of the left lateral ventricle. The tumor was removed "en bloc". Histological examination of the tumor revealed a choroid plexus carcinoma, which was considered met the criteria given by Russell and Rubinstein. The postoperative course was very complicated with metastasis to the right tibia, which was verified by needle biopsy. The patient died from a cachexia. This case was the youngest of all reported cases and very unique in the point of which the tumor metastasized to outside of the central neural axis.
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PMID:[Choroid plexus carcinoma with metastasis to bone (author's transl)]. 49 63

Interaction of positively charged liposomes with Ehrlich ascites tumor cells increases the bidirectional transmembrane fluxes of the anionic folic acid analog, methotrexate. Negative liposomes reduce methotrexate influx. Stimulation of methotrexate influx by positively charged liposomes is time and concentration dependent, requiring at least a 5-min incubation with 2.5 mM phosphatidylcholine containing 20% stearylamine for maximum effect. Stimulation is not appreciably reversed by washing the cells. Similar increases are observed for influx and efflux so that there is no change in the steady-state methotrexate electrochemical-potential difference across the cell membrane. The increase influx appears to be a stimulation of the carrier-mediated transport process for methotrexate since both control and stimulated influx are abolished by the competitive inhibitor, 5-formyltetrahydrofolate or the sulfhydryl group inhibitor, p-chloromercuriphenylsulfonic acid and the Q10 of the system remains unchanged. Influx of 5-methyltetrahydrofolate, which shares the same transport carrier as methotrexate, is also stimulated. However, the transport of folic acid, which is structurally similar to methotrexate but does not utilize the carrier, is unaffected. The kinetic change induced by positively charged liposomes is an increase in the Vma in, while the Kt in remains unchanged. Trans-stimulation of methotrexate influx by 5-formyltetrahydrofolate occurs to the same extent in the presence or absence of positively charged liposomes. The liposomes have no apparent effect on the intracellular water, the extracellular space, or the chloride distribution ratio. The data suggest that interaction of positively charged liposomes with Ehrlich ascites tumor cells accelerates the rate of transposition of the membrane carrier system for methotrexate, altering the kinetics of transport without a change in transport thermodynamics.
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PMID:Alterations of the carrier-mediated transport of an anionic solute, methotrexate, by charged liposomes in Ehrlich ascites tumor cells. 50 33

Steady-state fluxes of 86Rb+ (as a tracer for K+) were measured in Chinese hamster ovary cells (CHO-K1) and a mutant (CR1) defective in the regulation of cholesterol biosynthesis; the membrane cholesterol content of this mutant was varied by growing it on a range of cholesterol supplements to lipid-free medium (Sinensky, M. (1978) Proc. Natl. Acad. Sci. U.S. 75, 1247--1249). Analogous to previous findings in ascites tumor cells, 86Rb+ influx in the parent strain was differentiated into a ouabain-inhibitable 'pump' flux, furosemide-sensitive, chloride-dependent exchange diffusion, and a residual 'leak' flux. On the basis of this flux characterization, 86Rb+ pump and leak fluxes were measured in the mutant as a function of membrane cholesterol content. Pump and leak fluxes, when expressed per ml cell water, were independent of the cholesterol content of the mutant. Moreover, 86Rb+ fluxes in the mutant were equal to those in the parent strain. Our data imply that the flux behavior of K+ in the steady state is independent of the ordering of membrane lipid acyl chains.
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PMID:86Rb+ fluxes in Chinese hamster ovary cells as a function of membrane cholesterol content. 50 50

Addition of 4 ppm Se to the drinking water of male albino rats fed diets containing 0.03% 2-acetylaminofluorene (AAF) provided protection against hepatic damage and also resulted in at least 50% reduction in liver tumor incidence. An in vitro assay system utilizing microsomes from Se supplemented or non-supplemented 3-methylcholanthrene (MC) induced rats was used to determine the effect of oral Se intake on the metabolism of AAF. Oral Se administration led to an increase in ring hydroxylation and a decrease in N-hydroxylation. Addition of Se to the microsomal assay system increased 3-OH AAF formation and decreased N-OH AAF formation, thus shifting the balance of metabolism toward detoxification pathways.
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PMID:Selenium effects on the carcinogenicity and metabolism of 2-acetylaminofluorene. 50 11

For 14 months 200 white noninbred male rats received N-methyl-N'-nitro-N-nitrosoguanidine in various concentrations in drinking water. The animals were sacrificed in 18--22 months. Out of 178 rats surviving the time of appearance of the first tumor 64 animals developed tumours of the gastrointestinal tract. Histologically, gastric tumours in 34 cases were presented by adenomatous outgrowths, in 11 the changes were extremely suspect of cancer, in 2 cases morphologically true cancer was observed. The induced gastric tumours had certain peculiarities as compared with the corresponding tumours of man which consisted in tumour cells growing through the thickness of the wall without marked atypism and lack of metastases. Intestinal tumours were sarcomas in which simultaneously some mesenchymal components were present.
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PMID:[Morphology of gastrointestinal tract tumors induced in rats by N'-nitro-N-nitrosoguanidine]. 51 62

The effect of phenobarbital on simultaneous induction of liver and lung tumors was examined in inbred DDD mice. Group 1 of newborn mice received a single intraperitoneal (ip) injection of dimethylnitrosamine (DMN) and after weaning they were given 0.05% phenobarbital solution to drink. Group 2 received an injection of DMN like Group 1 but were then given normal water. Group 3 were injected ip with 0.9% NaCl solution and then given phenobarbital solution to drink as in Group 1, and Group 4 were injected with 0.9% NaCl solution like Group 3, and then given tap water to drink. The animals were examined 16 weeks after birth. In Group 1, 27 of 35 mice (77%) had liver tumor and 15 (43%) had lung tumor. In Group 2, 8 of 24 mice (33%) had liver tumor and 16 (67%) had lung tumor. Animals in Groups 3 and 4 did not develop tumors. The difference in the incidences of liver tumor, but not lung tumor, in Groups 1 and 2 was statistically significant (P less than 0.01); that is, a promoting effect of phenobarbital was observed in induction of liver tumor, but not lung tumor.
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PMID:Effect of phenobarbital on induction of liver and lung tumors by dimethylnitrosamine in newborn mice. 52 Jul 54


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