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

MTT staining procedures have been used in chemosensitivity testing of established cell lines of human and other sources as well as of human leukaemias, but only limited information on its application in primary solid human tumors is presently available. We have evaluated MTT staining in primary human Renal Cell Carcinomas (RCCs), studied various factors interfering with the optimal use, and finally applied it in subsequent chemosensitivity testing. The method depends on the conversion of a water-soluble tetrazolium salt (MTT) to a purple colored formazan precipitate, a reaction effected by enzymes active only in living cells. Single cell suspensions of RCCs were obtained either by enzymatic dispersion or by mechanical dissagregation, filtered through gauze, and purified by Ficoll density centrifugation. Tests were carried out in 96-well microculture plates. 10(4) viable tumor cells per well at 4 h incubation time with 20 micrograms MTT/100 microliters total medium volume yielded best results. Formazan crystals were dissolved with DMSO, and the plates were immediately measured on a microculture plate reader at 540 nm. Under these criteria, linearity of the system could be demonstrated. For chemosensitivity testing, cells were continuously exposed to a number of drugs prior to the MTT staining procedure. Reproducibility of results was assessed and confirmed by culturing RCCs in flasks additionally, resubmitting them after 1, 2, and 4 weeks to the MTT assay. We conclude that the semiautomated MTT assay offers a valid, rapid, reliable and simple method to determine the degree of chemoresistance in primary human RCCs.
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PMID:Chemosensitivity testing of primary human renal cell carcinoma by a tetrazolium based microculture assay (MTT). 169 48

Patients suffering from malignant disease will probably develop some metabolic abnormality of electrolytes. Hypernatremia is defined as an elevation of serum natrium over 150 mEq/l and caused by decrease of water intake, low level of ADH secretion and impaired response of kidney to ADH. Hyponatremia below 135 mEq/l of serum natrium is caused by SI-DAH, sick cell syndrome and increased loss of natrium from the kidney. On the other hand, hyperkalemia is defined as an elevation of serum kalium over 5.0 mEq/l and caused by acute tumor cell lysis syndrome, adrenal and renal insufficiency. Hypokalemia is caused by kalium loss from kidney and hypersecretion of mineral corticoid. Hypercalcemia is found in the high frequency among patients with malignant disease. Hypercalcemia is defined as an elevation of serum calcium over 11.0 mg/dl, although the most important aspect is the level of ionized calcium. The excess calcium causes defective urinary concentration with polydipsia, nausea and vomiting leading to volume depletion. At serum calcium levels about 13.8 mg/dl, there may be rapid deterioration or renal function, dehydration, coma and cardiac arrhythmias. Hypercalcemia is rarely the first manifestation of cancer. There are three principle pathogenic causes of malignant hypercalcemia, 1) hypercalcemia is a feature of several hematological cancers, including Burkitt's lymphoma, T cell leukemia, but most commonly with myeloma. The hypercalcemia in these myeloma patients is due to the secretion of an osteoclast activator, a lymphokine by the myeloma cells. 2) all patients with bony metastases have biochemical evidence of increased bone resorption. However, not all patients with bony metastases develop hypercalcemia. Probably the hypercalcemia is due partially to increased renal tubular reabsorption of calcium, mediated by a humoral factor, with activity similar to that of parathormone. 3) hypercalcemia in the patients without bony metastases is due to increased bone resorption caused by the ectopic secretion by the tumor. Mildly symptomatic patients will benefit from modest salt loading. They are dehydrated and replacement of the extracellular fluid is the first line of treatment. This may require 4-10 l normal saline/24 h. In addition, frusemide will increase calcium excretion. Calcitonin may be given subcutaneously or intravenously to refuse the mobilisation of calcium from bone. Glucocorticoids are unhelpful, but will prolong the effect of calcitonin. A diphosphonate is also useful.
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PMID:[Palliative therapy in cancer. 4. Palliation of the symptoms from a malignant tumor. (2)]. 169 56

To evaluate the mechanism of the promoting effect of goitrogens on thyroid tumorigenesis, well-known goitrogens having different pharmacologic action, i.e., thiourea, phenobarbital sodium (PB), potassium thiocyanate (KSCN), and 3,4,5,6-tetrachloro-2',4',5',7'-tetraiodo-fluorescein sodium salt (Rose Bengal B, FD&C Red No. 105) (FR105) were administered to the DHPN-initiated and non-initiated F344 male rats in the drinking water for 25 weeks. Remington's iodine deficient diet (I-def) was fed as a positive control. These goitrogens showed significant tumor promoting effect or promoting tendency on the rat thyroids. According to the changes in thyroid morphology and thyroid-related hormone titers observed in the present study, we proposed to classify goitrogens at least into 2 groups, i.e., iodine deficiency-type promoters and the iodine excess-type promoters. The former contains goitrogens inducing TSH-stimulated diffuse goiter composed of uniform follicles with activated tall follicular epithelial cells, such as thiourea, KSCN and PB, and the latter contains goitrogens inducing colloid goiter composed of a mixture of colloid-rich follicles with flat follicular cells and normal-looking follicles with cuboidal follicular cells, such as FR105. This classification may be useful for the risk assessment of goitrogens.
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PMID:Tumor promoting effect of goitrogens on the rat thyroid. 169 77

Calcium valproate is an anticonvulsant agent with pharmacokinetic properties similar to sodium valproate and valproic acid. Potential carcinogenesis of calcium valproate was evaluated in B6C3F1 mice and Wistar rats given 125, 250 and 500 mg/kg in the diet for 104 weeks. Survival in treated rats increased in a dose-related pattern despite a tumorigenic response in females. Adenocarcinomas of the uterus and cervix were increased in treated rats when compared to controls. The incidence of uterine neoplasia was 8, 20, 14 and 32% in the control, 125, 250 and 500 mg/kg groups, respectively. Neoplasia in treated rats were detected against a higher than expected background of adenocarcinomas in concurrent controls, since 8% incidence in controls was substantially above the laboratory historical database value of 0.6%. Tumors varied from epithelial masses confined to the endometrium, to transmural, highly desmoplastic neoplasms that invaded the serosa lining and the peritoneal cavity. These tumors metastasized in treated rats but not in controls. The statistically significant (P less than 0.01) increase in uterine adenocarcinomas found in females given 500 mg/kg of calcium valproate contrasts the absence of this tumor type in a previous rat carcinogenicity bioassay with valproic acid. Subcutaneous fibrosarcomas were significantly increased in valproic acid-treated males, but no uterine tumors were reported in females. It is puzzling that a true carcinogenic potential would be expressed by markedly different target organs as obtained with the acid and calcium salt of this moiety.
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PMID:Calcium valproate-induced uterine adenocarcinomas in Wistar rats. 172 66

A new tetrazolium analog of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) was evaluated as a substitute for MTT in the microculture screening assay for in vitro cell growth. This new tetrazolium compound, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium, inner salt (MTS), in the presence of phenazine methosulfate (PMS), gave a water-soluble formazan product that had an absorbance maximum at 490-500 nm in phosphate-buffered saline. The amount of colored product formed was proportional to the number of cells and the time of incubation of the cells with MTS/PMS. MTS/PMS was reactive in all the cell lines tested which included mouse leukemia L1210 cells, mouse Ehrlich tumor cells, mouse 3T3 fibroblasts, and human colon tumor cells (HT-29). HT-29 and 3T3 fibroblasts reduced MTS/PMS more efficiently than they reduced MTT. Comparable to the amount of product formed from MTT, MTS/PMS gave excellent product formation. The IC50 value for pyrazoloimidazole obtained using MTS/PMS was 200 microM; for 5-fluoro-2'-deoxyuridine, the IC50 value was 0.9 nM. These values compared very favorably with the IC50 values obtained by direct cell counts. Further, the same IC50 values were obtained when the absorbances of the formazan product in the 96-well plates were determined after different times of incubation.
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PMID:Use of an aqueous soluble tetrazolium/formazan assay for cell growth assays in culture. 186 54

Using novel strategies, monoclonal antibodies (MAbs) were developed to two proliferation-associated nucleolar antigens. These two new antigens, termed P145 and P120, according to their molecular weights, were found in a broad range of tumor tissues. Overall, P120 was more restricted in its distribution than P145 because it was absent from many benign tumors and some malignant tumors. Using the MAbs as probes, antigens P145 and P120 were localized to separate nucleolar components. P145 was mainly associated with high molecular weight nucleolar RNPs. Antigen P120 was localized to a novel beaded microfibril found in a nucleolar residue fraction. DNAse and high salt treatment of this fraction provided optimal extraction of the P120 antigen. P145 and P120 differed from other proliferation-associated nuclear/nucleolar antigens identified by autoimmune sera and by other MAbs. In PHA stimulated lymphocytes, both antigens were expressed in early G1 prior to or concurrent with increased RNA Pol I transcription. Microinjection of tumor cells with the P120 MAb inhibited cell proliferation and blocked the appearance of nucleolar pleomorphism that is characteristic of tumor cells. Clinical studies showed that P145 was not detected in normal bone marrow but was expressed in leukemic marrows (AML); the percentage of P145 positive cells correlated with percentage of malignant blasts (Raza et al., Am. Soc. Hematology, 1990). Antigen P145 was detected in 10 of 39 marrows from patients in complete remission. This result suggested that these cells have a higher proliferative potential than normal stem cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Monoclonal antibodies to human tumor nucleolar antigens: probes for studying biological function and determining clinical significance. 187 97

[14C]Glucosamine metabolic labeling and concanavalin A blots were used to identify four major glycoprotein species associated with ascites tumor cell microvillar microfilament cores and with a transmembrane complex containing actin. Phalloidin shift analysis of glucosamine-labeled microvilli showed that glycoproteins of 110-120, 80, 65, and 55 kDa are stably associated with the microfilament cores. Analysis of large (greater than 10(6) kDa) transmembrane complexes from microvillar membranes made under microfilament-depolymerizing conditions (Carraway, C. A. C., Jung, G., and Carraway, K. L. (1983) Proc. Natl. Acad. Sci. U. S. A. 80, 430-434) revealed glycoproteins of the same Mr values, showing the same relative staining or labeling patterns as those observed with the microfilament cores. Gel filtration of high salt, high pH extracts of intact microvilli, microfilament cores, or transmembrane complexes showed that in all of these fractions the glycoproteins are associated in a very large, stable complex. The glycoprotein multimer was isolated essentially free of actin and other components by Sephacryl S-1000 chromatography of microvilli, microvillar membranes prepared at pH 11, microfilament cores, or transmembrane complex fractions in Triton X-100, 1 M KCl, glycine, pH 9.5. Purified glycoprotein complex bound actin when incubated under polymerizing conditions. The presence of the glycoprotein heteromultimer in both microfilament cores and transmembrane complex from isolated membranes and the association of the purified glycoprotein complex with actin are consistent with our hypothesis that the glycoprotein-containing transmembrane complex is an association site for microfilaments at the plasma membrane.
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PMID:Membrane-microfilament interactions in ascites tumor cell microvilli. Identification and isolation of a large microfilament-associated membrane glycoprotein complex. 187 53

Mice fed menhaden (fish) oil or coconut oil-rich diets were inoculated intraperitoneally with a rapidly growing leukemia, T27A. After one week, the tumor cells were harvested, and 51Cr was used to label intracellular molecules. Spontaneous release of 51Cr was used as a measure of plasma membrane permeability. Compared to cells from mice fed coconut oil (rich in saturated fatty acids), tumor cells from mice fed menhaden oil (rich in long chain polyunsaturated omega 3 fatty acids) showed an increased level of spontaneous 51Cr release, which was exacerbated by increased temperature and reduced by extracellular protein. At physiological salt concentrations, the released 51Cr was detected in particles of approximately 2700 daltons. Enhanced permeability correlated with the incorporation of dietary (fish oil) omega 3 polyunsaturated fatty acids docosahexaenoic and eicosapentaenoic acid into the tumor cells. The results demonstrate that omega 3 fatty acids are incorporated into cellular constituents of tumor cells and change properties associated with the plasma membrane. This result suggests that dietary manipulation may be used to enhance tumor cell permeability and contribute to tumor eradication.
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PMID:Omega 3 fatty acids increase spontaneous release of cytosolic components from tumor cells. 189 81

Nuclear proteins obtained from human brain tumor cell lines by differential salt extraction were subjected to high-resolution two-dimensional electrophoresis. Several hundred spots were detectable in the low salt (0.4 M NaCl) extract using silver staining. These patterns exhibited remarkable differences between the different cell lines we analyzed. A less complex pattern occurred when nuclei were subsequently treated with high salt (2.5 M NaCl/5 M urea). We compared the electropherograms from various human glioblastoma cell lines and found them very similar and even a high degree of similarity occurs between glioblastomas and other human tumor cell lines. Beside these more general observations we detected several proteins at least enriched in human glioblastomas which were totally absent in low grade astrocytomas and nonglial tumors. They could be separated from the bulk of nonspecific proteins by simple modifications of the isoelectric focusing conditions. From these results we conclude that nuclear proteins obtained by sequential salt extraction and separated by two-dimensional techniques may provide tumor specific proteins suitable for antibody production.
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PMID:Nuclear and DNA-binding proteins in human brain tumors. 191 44

Excess production of aldosterone secondary to an adrenal tumor or bilateral hyperplasia is a known, but infrequent, cause of hypertension. A more frequent adrenal abnormality, observed in 30-40% of hypertensive patients, is a functional derangement in aldosterone secretion. Two such conditions have been described: low renin essential hypertension and non-modulating essential hypertension. Both have in common 1) an abnormality in the interaction of angiotensin II (Ang II) with the adrenal and 2) sodium sensitivity of the blood pressure. However, the pathophysiological mechanisms for the sodium sensitivity and hypertension are different. In normal subjects, the response of the adrenal glomerulosa cell to Ang II varies with the level of sodium intake, with sodium restriction enhancing the response. In one group of hypertensive patients with low plasma renin levels, the normally reduced aldosterone responses to Ang II on the high salt diet do not occur. Thus, these individuals have an enhanced adrenal response to Ang II under circumstances in which it should be reduced, thereby leading to lower renin levels and a tendency toward sodium retention. The second group has the opposite defect; that is, on a low sodium diet, they have a reduced adrenal response to Ang II. This results in a normal or high plasma renin level. The sodium sensitivity of their blood pressure arises not from the adrenal abnormality but from the associated defect in sodium-dependent, Ang II-mediated changes in renal blood flow. Thus, on a high salt diet, these patients, who are termed "non-modulators," fail to increase renal blood flow, thereby leading to a sodium-retaining state.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Functional derangements in the regulation of aldosterone secretion in hypertension. 193 78


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