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Query: UMLS:C1832526 (PCC)
 5,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surgical specimens of 64 adrenal PCCs were investigated by conventional histology, immunocytochemistry and DNA-cytophotometry. Tumour weights of more than 200 g were recorded for each of the 6 malignant, but for only one of the 58 clinically benign neoplasms. Increased mitotic activity (greater than 5 mitoses/10 HPF) was, apart from one benign lesion, only seen among malignomas. Immunocytochemically, all malignomas were entirely devoid of S100-positive sustentacular cells and, as compared to benign PCCs, showed reduced expression rates of different neuropeptides. Upon cytophotometry, only 5/43 tumours exhibited euploid DNA histograms, all these cases belonging to the group of benign PCC. According to these findings, morphology does not enable a definite prediction of the clinical course of individual PCC cases, but renders the definition of risk groups possible. A benign diagnosis can be made in multihormonal euploid tumours weighing less than 200 g. In larger neoplasms and in cases lacking sustentacular cells and showing increased mitotic activity, an unfavourable prognosis is to be suspected and the same therapeutic procedures should be applied as for tumours in which malignancy is evident in metastatic growth.
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PMID:[Histology, immunocytochemistry and DNA cytophotometry of adrenal glandpheochromocytoma (PCC)--a morphologic clinal study of 64 tumors]. 170 5

The technique of fusing mitotic cells to interphase cells, thereby producing condensation of the chromosomes of the interphase cell (so-called 'premature chromosome condensation' or PCC), has allowed detection of the initial number of chromosome breaks and their repair following ionising radiation. However, the difficulty and tedium of scoring all the chromosome fragments, as well as the inability to readily detect exchange aberrations, has limited the use of PCC. We describe here the use of the recently developed technique of fluorescence in situ hybridisation with whole chromosome libraries to stain individual human chromosomes (also called 'chromosome painting') with the PCC's and show that this overcomes most of the limitations with the analysis of PCC's. First, by focusing on a single chromosome, scoring of breaks in the target chromosome is easy and rapid and greatly expands the radiation dose range over which the PCC technique can be used. Second, it allows the easy recognition of exchange type aberrations. A number of new applications of this technology, such as predicting the radiosensitivity of human tumours in situ, are feasible.
Br J Cancer 1991 Apr
PMID:The use of fluorescence in situ hybridisation combined with premature chromosome condensation for the identification of chromosome damage. 202 36

Beginning in early S phase, synchronized Chinese hamster ovary cells were heated for 12 h at 41.5 degrees C, during which time the cells progressed through S, G2, and into mitosis. Upon return to 37 degrees C, some of the interphase cells developed a fragmented nuclear morphology, and the fraction of cells exhibiting this effect reached 40% after entering the first mitosis. About 50% of the mitotic cells accumulated with Colcemid at the second mitosis exhibited premature chromosome condensation (metaphase-associated PCC) in an amount equal to approximately one to two chromosomes per diploid cell. There was also a low frequency of spontaneous S and G2 PCC (0.5 to 1.5% in controls); this distinctly different type of PCC was observed in heated interphase cells at a frequency of 2.0 to 7.0% before the first wave of entry into mitosis. Heated S-phase cells exhibited a chromosome break frequency of about 0.9 breaks per cell when analyzed at the first mitosis. This value agrees well with the observed surviving fraction of 40%, if we assume that one break per cell is a lethal event, and that chromosome damage has a Poisson frequency distribution in the cell population; however, this correlation may not be valid for tumor cell populations. Between the first and second mitoses, an increase in hyperthermia-induced aneuploidy was observed which was apparently due to unequal division, since mitotic cells containing PCC were excluded from the chromosome number frequency analyses. Although this induction of aneuploidy was observed independently of PCC, we conclude that abnormal division is necessary for both effects, and both PCC and unequal division result in an increase in aneuploidy. Previous studies using transmission electron microscopy demonstrated a precocious reformation of the nuclear membrane around metaphase chromosomes in Chinese hamster ovary cells heated at this temperature (R. A. Coss et al., Cancer Res., 39: 1911-1918, 1979). We suggest that such heat-induced changes in nuclear envelope formation lead to nuclear fragmentation and ultimately result in metaphase-associated PCC.
Cancer Res 1988 Nov 15
PMID:Nuclear fragmentation and premature chromosome condensation induced by heat shock in S-phase Chinese hamster ovary cells. 318 64

Carcinomas of the plexus choroideus (PCC) represent the rare malignant variety of plexus choroideus papillomas and take a particularly unfavourable course. Tumors of the plexus choroideus account for about 2-4% of all primary brain tumors in children and 0.5% of those in adults. The PCC is more frequent in children than in adults; the authors found reports on 72 cases of PCC in children and on 16 cases in adults. In most cases the PCC is located in the lateral ventricles. The symptoms caused by PCC are non specific and appear as those of increased intracranial pressure (on the basis of hydrocephalus hypersecretorius and/or occlusivus). As the nature of the tumor cannot be identified by means of medical imaging, the diagnosis is usually set up histologically. Prognosis is poor for patients treated only by surgery, which in most cases has been performed as subtotal resection of the tumor. So the necessity for an oncological strategy combining surgery and 'adjuvant' therapy arises. The authors report the application of such a strategy in the case of a three-year-old boy with a PCC of the left lateral ventricle. After nearly four years of remission, the boy died of meningeosis carcinomatosa. This course underlines the malignancy of this tumor; even after years the poor prognosis can still be diminished by the spread of meningeal metastases. In a survey of the case reports published in literature the patients' data, their therapy and the outcome are demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Therapy of choroid plexus carcinoma in childhood. Case report and review of the literature]. 775

The spontaneous onset of autoantibodies against circulating factors, including factors II, V, VII, VIII, IX, XI, XII, and XIII, is a phenomenon of unclear causes. It may occur in patients with no underlying disease process or may be antedated by autoimmune diseases and malignancies. The antibodies are almost always IgG and are most commonly directed at F VIII. They generally present with a bleeding diathesis in patients with no history of prior bleeding events. The laboratory abnormalities vary depending on whether the inhibitor involves the intrinsic or extrinsic pathway of coagulation, and the laboratory studies may vary depending on the technique used. Supportive measures are used initially but are generally not completely effective. Supportive measures are followed by blood products, such as recombinant human F VIII, porcine F VIII, or PCC/aPCC. There are limitations to each of these, however. If bleeding is severe and high titers of inhibitors are present, plasma-pheresis may lead to a temporary decrease in the titer but is short-lived. Immunosuppressive therapy should ultimately be attempted to suppress further antibody production. Spontaneous remission may occur with some of the inhibitors, primarily postpartum or drug related, for reasons not fully understood.
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PMID:Autoimmune coagulation disorders. 915

The effect of cisplatin-containing chemotherapy regimen was evaluated on the expression of HLA-DR antigen in peripheral blood monocytes from patients with lung (LCP) and colorectal (CCP) cancer. Chemotherapeutic schedules employed in patients were etoposide and cisplatin for LCP and 5-fluorouracil and cisplatin for CCP. The results obtained showed a diminished percentage of monocytes expressing HLA-DR antigen in LCP (52.4 +/- 2.6, p < 0.004) and CCP (50.1 +/- 2.1, p < 0.001) respectively versus healthy donors (71.0 +/- 1.1%), and that their values increased during chemotherapy, raising them up to control level after the second cycle of treatment, independently of the course of the cancer growth. We conclude that both modalities of treatment allowed an increase of monocytes expressing HLA-DR antigen, suggesting that this effect may be due to cisplatin action.
J Exp Clin Cancer Res 1999 Dec
PMID:Cisplatin containing chemotherapy influences HLA-DR expression on monocytes from cancer patients. 1074 74

Condensing enzymes, catalyzing the formation of carbon-carbon bonds in several biosynthetic pathways, have lately been recognized as potential drug targets against cancer and tuberculosis, as crucial for combinatorial biosynthesis of antibiotics and related compounds, and as determinants of plant oil composition. beta-Ketoacyl-ACP synthases (KAS) are the condensing enzymes present in the fatty acid biosynthesis pathway and are able to elongate an acyl chain bound to either co-enzyme A (CoA) or acyl carrier protein (ACP) with a two-carbon unit derived from malonyl-ACP. Several isoforms of KAS with different substrate specificity are present in most species. We have determined the crystal structure of KAS II from Synechocystis sp. PCC 6803 to 1.54 A resolution giving a detailed description of the active site geometry. In order to analyze the structure-function relationships in this class of enzymes in more detail, we have compared all presently known three-dimensional structures of condensing enzymes from different pathways. The comparison reveals that these enzymes can be divided into three structural and functional classes. This classification can be related to variations in the catalytic mechanism and the set of residues in the catalytic site, e.g. due to differences in the nature of the second substrate providing the two-carbon elongation unit. The variation in the acyl-carrier (ACP or CoA) specificity might also be connected to this classification and residues involved in ACP binding in structure class 2 can be suggested based on the comparison. Finally, the two subunits in the dimer contribute differently to formation of the substrate binding-pocket in the three structural classes.
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PMID:The crystal structure of beta-ketoacyl-acyl carrier protein synthase II from Synechocystis sp. at 1.54 A resolution and its relationship to other condensing enzymes. 1115 7

Commercial processing wastes or by-products of crops were found to be sources of antimutagens and human tumor cell growth suppressors. We developed a microplate method to measure genomic DNA damage in Chinese hamster ovary cells with a modified single cell gel electrophoresis (SCGE) assay. This allowed us to measure the repression of 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage by very small amounts of complex mixtures, fractions or individual chemicals isolated from agricultural by-products. We previously demonstrated that PCC, an ethanol extract of a commercial soybean processing by-product, repressed induced genomic DNA damage in mammalian cells. PCC was separated into a series of chemically defined fractions and two fractions (PCC70 and PCC100) repressed mutagen-induced damage. Of the isoflavones isolated from soybean fraction PCC70, daidzein expressed antigenotoxic activity, however, genistin and genistein enhanced DNA damage. An antigenotoxic response also was observed with a fraction isolated from corn distillate solids (CDS40). We developed a microplate assay to measure the suppression of the growth rate of human cancer cells in which the cytostatic/cytotoxic status at each concentration of the test sample was quantitatively determined. Genistein, genistin, daidzein and daidzin isolated from soybean fraction PCC70 expressed a wide range of growth suppression of HT-29 human colon cancer cells. The biological assays were integrated with, and directed, the separation and analytical chemistry component of this project. Compounds were purified from biologically active fractions and the structure of individual chemicals was determined with analytical HPLC and LC-mass spectroscopy (LC-MS). This research may lead to the isolation of novel chemoprotectants from agronomic commercial processing products and by-products.
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PMID:Isolating antigenotoxic components and cancer cell growth suppressors from agricultural by-products. 1150 4

Propylene is a major industrial intermediate and atmospheric pollutant to which humans are exposed by inhalation. In this study, 6-week-old male F344 rates were exposed to 0, 200, 2000, or 10,000 ppm propylene by inhalation for 4 weeks (6 h/day, 5 days/week), and mutant frequencies were determined in the Hprt gene of splenic T-lymphocytes. Twenty milligrams of cyclophosphamide monohydrate (CPP)/kg bw, given on the penultimate day of propylene exposure, was used as a positive control mutagen. Rats (n = 8/group) were necropsied for isolation of T-cells 8 weeks after the last dose, a sampling time that produced peak spleen Hprt mutant frequencies (Mfs) in a preliminary mutant manifestation study using CCP treatment. Hprt Mfs were measured via the T-cell cloning assay, which was performed without knowledge of the animal treatment groups. Mean Hprt Mfs were significantly increased over control values (mean Mf = 5.24 +/- 1.55 (SD) x 10(-6)) in CPP-treated rats (10.37 +/- 4.30 x 10(-6), P = 0.007). However, Hprt Mfs in propylene-exposed rats were not significantly increased over background, with mean Mfs of 4.90 +/- 1.84 x 10(-6) (P = 0.152), 5.05 +/- 3.70 x 10(-6) (P = 0.895), and 5.95 +/- 2.49 x10(-6) (P = 0.500) for animals exposed to 200, 2000, or 10,000 ppm propylene, respectively. No significant increase in F344 rat or B6C3F1 mouse cancer incidence was reported in the National Toxicology Program carcinogenicity studies of propylene across this same exposure range. Taken together, these findings support the conclusion that inhalation exposure of rats to propylene does not cause mutations or cancer.
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PMID:Hprt mutant frequencies in splenic T-cells of male F344 rats exposed by inhalation to propylene. 1514 66

Gadolinium neutron capture therapy (Gd-NCT) is an experimental cancer treatment based on the physical principal that neutron capture by gadolinium-157 ensures the release of focal high-dose radiation, such as gamma-rays and electrons. Survival and induction of chromosomal aberrations of human SW-1573 cells was studied after thermal neutron irradiation without and with gadolinium. After neutron irradiation with Gd-DTPA, an alpha-enhancement factor of 2.3 was obtained compared to thermal neutron irradiation alone. Gd-DTPA could not radioenhance the cells for gamma-ray irradiation. Induction of colour junctions and chromosome fragments by thermal neutron irradiation and Gd-NCT were studied using PCC-FISH. Correlations (r2-value) between survival and chromosome aberrations ranged from 0.81 to 0.94 for colour junctions and from 0.78 to 0.98 for chromosome fragments of chromosomes 18 and 2 respectively. Thermal neutron irradiation with or without gadolinium induced more chromosome aberrations than gamma-ray irradiation. After correction for chromosome length it appeared that both chromosomes were equally sensitive to radiation. It is concluded that Gd-NCT at a non-toxic concentration of gadolinium is effective in inducing cell death and chromosome aberrations in in vitro cell cultures.
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PMID:Gadolinium enhances the sensitivity of SW-1573 cells for thermal neutron irradiation. 1646 35


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