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

The importance of phosphatases in regulating the phosphorylation of proteins involved in cell signaling has been demonstrated by four recent discoveries. First, a new family of receptor-like transmembrane phosphotyrosine phosphatases, highly conserved throughout evolution, was shown to be distributed in a wide variety of tissues. Extensive heterogeneity in the extracellular regions of these molecules points to the existence of a wide diversity of ligands. These ligands are thought to mediate transduction of signals to the cell interior by means of the phosphatase activity occurring within the cytoplasmic domains of the receptor-like transmembrane phosphotyrosine phosphatases. Second, cell-permeable tumor promoters, such as okadaic acid, were shown to be potent phosphatase inhibitors that have multiple effects on signaling pathways. Third, the subunits of the type 2A phosphatase were found to associate with transforming antigens encoded by DNA tumor viruses, indicating a role for phosphatases in mediating abnormal proliferative events. Fourth, several cell-cycle mutants were found to encode phosphatases. This review focuses on the significance of the transmembrane phosphotyrosine phosphatases and on the possible ways in which intracellular phosphatases function in signaling pathways.
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PMID:The role of phosphatases in signal transduction. 196 46

We have identified a highly active Ca2+ calmodulin-dependent protein kinase in the cytoskeletons of normal (bovine fasciculata) and transformed (Y-1 mouse tumor) adrenal cells. In view of evidence for the involvement of calmodulin and microfilaments in the regulation of cholesterol transport and hence steroidogenesis, it is likely that this kinase is important in this process. The kinase activity was examined for its capacity to phosphorylate endogenous proteins analyzed by one- and two-dimensional gel electrophoresis, in the presence of saturating amounts of Ca2+ (5 mM) and calmodulin (5 microM). Three inhibitors of calmodulin (trifluoperazine, pimozide and W-7) inhibit steroidogenesis and Ca2(+)-calmodulin-dependent phosphorylation kinase activity with similar values for EC50 for the two processes. All three inhibitors inhibit the increased transport of cholesterol to mitochondria in response to ACTH. Two substrates for the kinase (alpha-spectrin and beta-tubulin) were identified and two others (51,000 and 60,000 molecular weight) were tentatively identified as the subunits of the kinase itself in cytoskeletons of both cell types. Calmodulin-binding proteins analyzed by [125I]iodocalmodulin overlay and calmodulin-Sepharose affinity chromatography were also identified in the same cytoskeletons including alpha-spectrin, the Ca2+ calmodulin-dependent phosphatase calcineurin and three that were tentatively identified as the two subunits of the kinase itself and myosin light chain kinase. It is concluded that calmodulin, by binding to the kinase and phosphatase, is capable of influencing the degree of phosphorylation of specific substrates in the cytoskeleton and of forming complexes with spectrin, actin and tubulin. These events may be involved in the regulation of the rate-limiting step of steroidogenesis, i.e. transport of cholesterol to mitochondria.
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PMID:Calcium-calmodulin-dependent phosphorylation of cytoskeletal proteins from adrenal cells. 196 7

Protein phosphatase activities were analyzed in vivo in Xenopus oocytes. The dephosphorylation of microinjected beta casein was inhibited when the tumor promoter okadaic acid was microinjected into oocytes. Inhibition was dose dependent and reversible; 50% of activity was recovered 15-30 minutes after microinjection.
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PMID:Protein phosphatase activities in vivo in Xenopus laevis oocyte: inhibition by okadaic acid. 196 91

To determine the incidence and clinical significance of micrometastases in the bone marrow of breast carcinoma patients, we performed an immunoalkaline phosphatase assay using anticytokeratin (AE1, AE3, MAK-6) and antiepithelial (113F1, 260F9, 317G5) antibodies on the bone marrow aspirates of 71 stage IV disease patients with either recurrent regional or distant metastases. Although we detected tumor cells within the bone marrow of 38% of these patients with this assay, no significant correlation was seen with patient's age, menopausal status, bone scan, bone marrow core histology, response to induction chemotherapy, number of metastatic sites, dominant site of metastasis, or subsequent clinical outcome. The clinical parameters that were associated with improved survival were one dominant site of metastatic disease and regional soft tissue recurrence without distant disease.
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PMID:Detection of micrometastatic tumor cells in bone marrow of breast carcinoma patients. 202 19

The monoclonal antibody Ki-67 has been described in 1983 by Gerdes. Lymphocytes stimulated with PHA as well as a number of human tissues have been studied using the antibody. The results have shown, that the Ki-67 antigen is expressed by all cells in the active phases of the cell cycle not, however, by resting cells or the starting sequences of the cell cycle. Although the nature of the Ki-67 antigen ist not yet known, several studies have demonstrated that the Ki-67 growth fraction is a valuable parameter for characterization of malignant tumors. So far, the so-called "Ki-67 growth fraction" (Ki-67 GF) has been determined on non-Hodgkin-lymphomas and on malignant tumors of the bone, kidney and lung. The most extensive data are available on breast cancer. In the author's studies the APAAP-method (APAAP = "alkaline phosphatase-anti-alkaline phosphatase") is preferred as an immunohistochemical staining method. The median Ki-67 growth fraction of 261 breast carcinomas was 12.5% (range 1 to 65%), being five times higher than in benign breast tissue (n = 126). The Ki-67 GF of breast cancer was correlated to different parameters known to be related to prognosis. Thus, a correlation was found with the age of patients, tumor stage, histological grading and hormone receptor status. These results are similar to those obtained by autoradiography and flow cytometry. Of 141 patients the clinical outcome of disease is known (median follow-up 22 months): 25 patients have developed local recurrence of the chest wall. This group of patients showed no significant correlation to the Ki-67 growth fractions of the primary tumors. However, the Ki-67 GF was significantly higher in 20 patients with early systemic disease and in 19 patients who died from breast cancer. Based on these results a clinical trial on adjuvant chemotherapy of lymphnode-negative patients should be taken into consideration. Thus, the prognosis for early stage breast cancer might be improved.
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PMID:[In situ determination of the Ki-67 growth fraction (Ki-67 GF) in human tumors (studies in breast cancer)]. 208 Feb 54

A simplified method of processing of fine needle aspirates for paraffin miniblocks suitable for both morphologic and immunocytochemical evaluation is described. Aspirates were fixed in ethanol at 4 degrees C, dehydrated in acetone and xylene and embedded in paraffin (58 degrees C). All steps were carried out in a single Eppendorf centrifuge tube; the total process took less than four hours. Deparaffinized sections were stained using the alkaline phosphatase-antialkaline phosphatase technique with monoclonal and conventional antibodies helpful in the differential cytologic diagnosis of alcohol-fixed aspiration biopsy specimens. Antibodies to keratin, vimentin, desmin, neurofilaments, glial fibrillary acidic protein, leukocyte-common antigen, synaptophysin and immunoglobulin kappa and lambda light chains reacted positively on the miniblock material. Since the paraffin miniblocks combine the histologic pattern of the tumor with the differentiation-specific information provided by immunocytochemistry, their use can improve the accuracy of tumor typing in aspirates.
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PMID:Immunocytochemistry on fine needle aspirates in paraffin miniblocks. 214 Apr 87

We have purified the 36 and 63 kd cellular proteins known to associate with polyomavirus middle and small tumor (T) antigens and SV40 small t antigen. Microsequencing of the 36 kd protein indicated that it was probably identical to the catalytic subunit of protein phosphatase 2A (PP2A). Identity was confirmed by comigration on two-dimensional (2D) gels and by 2D analysis of complete chymotryptic digests. In addition, PP2A-like phosphatase activity was detected in immunoprecipitates of wild-type middle T. Immunoblotting experiments, comigration on 2D gels, and 2D analysis of limit chymotryptic digests demonstrated that the 63 kd protein, present in the middle T complex in approximately equimolar ratio to the 36 kd protein, is a known regulatory subunit of the PP2A holoenzyme. Finally, the 36 kd PP2A catalytic subunit can be immunoprecipitated by anti-pp60c-src antisera only from cells expressing wild-type middle T. These results suggest that complex formation between PP2A and T antigens may be important for T antigen-mediated transformation.
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PMID:Polyoma small and middle T antigens and SV40 small t antigen form stable complexes with protein phosphatase 2A. 215 55

The distribution of the beta-subunit of platelet-derived growth factor receptor (PDGFR-beta) was assessed by a sensitive immunoalkaline phosphatase technique using the monoclonal antibody PR7212. Frozen tissue sections of several nonneoplastic human tissues were stained along with 42 soft tissue sarcomas, 16 benign soft tissue proliferations, and 7 epithelial tumors. In all nonneoplastic tissue, there was intense labeling of cell processes of perivascular fibroblasts or pericytes in and about the walls of muscular blood vessels and of fibroblast cell processes around some glandular and ductal epithelia. No PDGFR-beta was found in the endothelial cells of muscular arteries and veins, but cells of uncertain identity within some capillaries were immunoreactive and the possibility that endothelial cells of some small capillaries express PDGFR-beta could not be excluded. In kidney there was strong labeling of glomerular mesangial cells and interstitial fibroblasts. Some histological types of soft tissue sarcomas were uniformly and strongly labeled with anti-PDGFR-beta, but other types were infrequently labeled or unreactive. The order of decreasing frequency and strength of labeling of the various types of benign and malignant soft tissue proliferations was as follows: benign fibromatosis and neurofibroma greater than malignant fibrous histiocytoma greater than liposarcoma greater than leiomyosarcoma greater than rhabdomyosarcoma. No tumor cell labeling was detected in epithelioid, synovial or clear cell sarcomas, leiomyomas, or carcinomas, but there was usually strong labeling of fibroblast and/or pericyte cell processes within tumor, especially around blood vessels. We conclude that PDGFR-beta is strongly expressed by vascular and stromal tissues of most tumors and normal organs and by tumor cells of several types of soft tissue tumors and proliferations, most notably those of fibroblastic origin.
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PMID:In situ distribution of the beta-subunit of platelet-derived growth factor receptor in nonneoplastic tissue and in soft tissue tumors. 216 45

A 31-year-old male patient with type Ia glycogen storage disease was admitted to our department complaining of general fatigue and right hypochondriac pain. He exhibited massive hepatomegaly with systemic hypoglycemia, lactic acidosis, hyperuricemia, hyperpyruvatemia and hyperlipemia. The failure of blood glucose levels to increase after a glucagon loading test, and a reduced lactate level on glucose tolerance test were also observed. Various imaging techniques suggested hepatic adenoma with hemorrhage in the tumor, which was confirmed histologically. There was a complete absence of glucose 6-phosphatase activity, as determined by an enzyme assay on resected liver specimens, which proved the case to be type Ia glycogen storage disease. We also reviewed all previously reported cases of hepatic tumor and glycogen storage diseases. We conclude that, since hepatic adenoma is not rare in this disease, and is complicated by hemorrhage, rupture and malignancy, careful follow-ups are necessary.
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PMID:A case of type Ia glycogen storage disease complicated by hepatic adenoma. 217 Feb 59

The authors report a case of choroidal osteoma in an elderly patient. The affection was bilateral and multifocal. This rare benign tumor mostly affects young females. We report the outcome of the clinical and instrumental examinations leading to the diagnosis of choroidal osteoma. The patient underwent retinal fluoroangiography, A and B-scan ocular ultrasonography, Computerized Axial Tomography (CAT) with and without dye, orbit RNM, and electroretinography. The same investigations were performed 6-7 months after the first control. No changes in the findings were found except for retinal fluoroangiograms that revealed an increased area of the most central lesion in the right eye. Particularly relevant among these diagnostic techniques were ocular ultrasonography and CAT, which revealed the osseous nature of the tumor. Contact B-scan ultrasound examination showed a small number of dense opacities in both eyes. In the retrobulbar area the tumor caused diminution in echo amplitude. A-scan examination showed high reflectivity peaks (100%) corresponding to the lesion that were detectable even with reduced sensitivity of the system and, in the orbit, low reflectivity that confirmed the tumor's enhanced ultrasound absorption. CAT detected small calcified areas corresponding to the location of the lesions. Haematochemical examinations performed at each control to measure blood calcium, phosphate and alcaline phosphatase were in the normal range. Urinalysis also excluded possible systemic affections underlying the chorioretinal pathology. We discuss possible pathogenetical hypothesis focusing on the age and sex of the patient. These factors in fact, rule out both the hypothesis of a osteogenesis inhibiting factor present in the last 20-30 years of age and the hypothesis of endocrine stimulation in female patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Bilateral choroidal osteoma in an aged patient]. 221 5


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