Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A fluorescence-based method for polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis, F-SSCP, was developed in which the target sequence is amplified by the PCR using fluorescent primers. The amplified products are then heat-denatured and applied to a water-jacket controlled gel in an automated DNA sequencer. The separated strands are detected as laser-excited fluorescence at the bottom of the gel, and mutations are detected as shifts in the position of the peaks in the fluorogram. The system does not involve radioactivity, and the conditions of electrophoresis are more strictly controlled than in the previous system, which relied on ambient air-cooling to maintain the gel at a constant temperature. The nature of the output data allows direct quantitative interpretation, and so the relative abundance of each allele in a mixture of two or more alleles can easily be estimated. The application of F-SSCP for detection of mutations and loss of heterozygosities of p53 in tumor tissues is reported.
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PMID:F-SSCP: fluorescence-based polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. 149 Jan 70

Different variations of the antigen retrieval technique using different retrieval solutions have been evaluated for their effectiveness in restoring the antigenicity of six intranuclear antigens, each of which is a potentially valuable prognostic indicator in formalin-fixed, paraffin-embedded tissue sections. The results of immunohistochemical staining for estrogen receptor, progesterone receptor, androgen receptor, p53 protein, proliferating cell nuclear antigen, and Ki-67 antigen were compared following the different antigen retrieval approaches. The strongest immunostaining signal with the clearest background was obtained by microwave heating of dewaxed paraffin sections for 10 minutes in 0.05 mol/L glycine HCl (pH 3.5) or in citrate buffer solution (pH 6). Urea solution, distilled water, and lead thiocyanate solution yielded improvements with some antigens, but less consistently and less impressively than glycine HCl buffer or citrate buffer. Following antigen retrieval nuclear staining was sharply defined and could be achieved consistently in a variety of tissues after formalin fixation for as long as 7 days. The duration of fixation, however, was an important variable; generally, the longer the fixation time the more vigorous the retrieval procedure required. This study demonstrates the ability to stain a variety of intranuclear antigens, which are not readily demonstrable otherwise, in formalin-paraffin sections with a high degree of consistency and reproducibility. The availability of methods that are effective in paraffin sections may facilitate studies of the possible value of these markers as prognostic indicators for predicting the response of major tumors to different forms of therapy. This study also provided insight into the basic principles of the antigen retrieval method, which may be helpful in attempts to develop a more uniformly standardized technique applicable to many different antigen systems.
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PMID:Strategies for improving the immunohistochemical staining of various intranuclear prognostic markers in formalin-paraffin sections: androgen receptor, estrogen receptor, progesterone receptor, p53 protein, proliferating cell nuclear antigen, and Ki-67 antigen revealed by antigen retrieval techniques. 792 19

The effects of treatment in a hydrated autoclave (121 degrees C, 2 atm for 20 min), microwave oven (in water), and simple heating (60 degrees C overnight in distilled water or 90 degrees C for 10 min in ZnSO4) on the stainability of 56 antigens by commercially available antibodies in formalin-fixed paraffin-embedded tissue sections were evaluated. The detectability of nuclear antigens, glycoprotein, lymphocytic surface markers, and chromogranin A was significantly and reproducibly improved by these treatments, whereas the detectability of viral antigens and peptide hormones was attenuated or unchanged. This enhancement includes not only the distinctiveness of the positive staining, but also the number of positive cells, as revealed by comparing serial sections. Among these four heating procedures, microwave heating and autoclaving were more effective than the others on p53, c-erbB-2, and CA125, whereas simple heating was best for smooth-muscle actin (HHF35 and CGA7). Generally the effects of the heating procedures for these antigens were consistent among the cases, but the effects on GFAP varied with the case. The alterations we observed could significantly influence the interpretation of immunohistochemical staining of currently popular tumor markers such as p53 in terms of their prevalence (28% vs 64% in gastric cancer; 36% vs 82% in metastatic liver cancer) and other diagnostically important markers.
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PMID:Alteration of immunoreactivity by hydrated autoclaving, microwave treatment, and simple heating of paraffin-embedded tissue sections. 751 73

Aggregation of the high-affinity receptors for IgE (Fc epsilon RI) on mast cells activates nonreceptor kinases and other enzymes, thereby initiating a complex biochemical cascade. We have employed a chemical cross-linker in order to stabilize the association of Fc epsilon RI with other cellular proteins that are involved in the early events. We reacted the water-soluble, membrane-impermeant chemical cross-linker 3,3'-dithiobis(sulfosuccinimidyl propionate) (DTSSP) with permeabilized rat mucosal mast cells of the RBL line and analyzed immunoprecipitates of the receptor in detergent lysates of cells that had biosynthetically incorporated [35S]cysteine. Gel electrophoresis revealed substantial amounts of nonreceptor components only when the cells had been reacted with DTSSP. Receptors isolated from cells whose receptor-bound IgE had been aggregated with antigen prior to cross-linking yielded a similar pattern of 35S-labeled proteins. However, when the cells had also been exposed to [gamma-32P]ATP, the proteins associated with the cross-linked, aggregated receptors revealed enhanced incorporation of 32P compared to those associated with cross-linked, unaggregated receptors. A variety of antibodies were used to try to identify the associated proteins. Of those tested for, two, the src-like kinase p53/56lyn and the delta isoform of protein kinase C, were associated with the cross-linked Fc epsilon RI in amounts much greater than could be accounted for by nonspecific cross-linking.
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PMID:Chemical cross-linking of IgE-receptor complexes in RBL-2H3 cells. 753 96

The questions of whether and how N-nitroso compounds (NOC) may be inducing cancer in humans are discussed. The principal subjects covered include nitrite-derived alkylating agents that are not NOC, reasons for the wide tissue specificity of carcinogenesis by NOC, the acute toxicity of nitrosamines in humans, mechanisms of in vivo formation of NOC by chemical and bacterial nitrosation in the stomach and via nitric oxide (NO) formation during inflammation, studies on nitrite esters, use of the nitrosoproline test to follow human gastric nitrosation, correlations of nitrate in food and water with in vivo nitrosation and the inhibition of gastric nitrosation by vitamin C and polyphenols. Evidence that specific cancers are caused by NOC is reviewed for cancer of the stomach, esophagus, nasopharynx, urinary bladder in bilharzia and colon. I review the occurrence of nitrosamines in tobacco products, nitrite-cured meat (which might be linked with childhood leukemia and brain cancer) and other foods, and in drugs and industrial situations. Finally, I discuss clues from mutations in ras and p53 genes in human tumors about whether NOC are etiologic agents and draw some general conclusions.
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PMID:Role of N-nitroso compounds (NOC) and N-nitrosation in etiology of gastric, esophageal, nasopharyngeal and bladder cancer and contribution to cancer of known exposures to NOC. 760 May 41

Immunocytochemical methods were examined for their sensitivity in the detection of nuclear antigens (proliferating cell nuclear antigen, Ki-67 associated proliferative antigen and p53 protein) in the leukemic cells. A comparative study of the biotin streptavidin enhanced peroxidase technique, the biotin streptavidin enhanced alkaline phosphatase technique and the indirect immunoperoxidase technique showed that the indirect immunoperoxidase technique was more sensitive than the other techniques for detecting p53 protein. The results of several fixation methods demonstrated that formalin and methanol, formalin and ethanol (1:9) and buffered formalin acetone gave good results for detecting p53 protein. In the eosinophils and neutrophils the endogenous peroxidase reaction disappeared after microwave heating for over three minutes. Thus enzyme pre-blocking of blood smears could be omitted. Four solutions for microwave treatment were tested. Excellent antigen retrieval was obtained with pH6.4, pH7.4 phosphate buffer saline and pH6.0 citric acid. However, the nuclear antigens could not be retrieved and the positive reaction could not be obtained after the treatment with distilled water. The optimal microwave heating time was five to ten minutes. The indirect immunoperoxidase technique performed using microwave treatment under these optimal conditions may be potentially applicable for detecting low levels of nuclear antigens in the leukemic cells within conventional blood smears.
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PMID:[Detection of nuclear antigen within the leukemic cells using immunocytochemical technique]. 778 70

Immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA) and p53 protein is important, particularly for the surgical diagnosis of neoplastic disorders. An effective, simple and reproducible method was established for observing the expression of these intranuclear antigens in routinely processed, formalin-fixed paraffin-embedded sections. Dramatic improvement of the antigenicity was obtained when the deparaffinized sections were heated in a hot water bath at 90 degrees C for 120 min in 0.01 mol/L citrate buffer, pH 6.0, for PCNA and in 0.01 mol/L phosphate-buffered saline, pH 7.2, for p53 protein. These reliable pretreatments are useful for the detailed comparative analysis of the expression of PCNA and p53 protein and fine histologic architecture and for retrospective study using a large number of archival specimens.
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PMID:Heat-induced antigen retrieval of proliferating cell nuclear antigen and p53 protein in formalin-fixed, paraffin-embedded sections. 783 77

One day old mangrove rivulus (Rivulus ocellatus marmoratus) were exposed to 9 mg/l diethylnitrosamine (DEN) for 6 weeks, kept in water without DEN for an additional 18-20 months, then necropsied. Oncogene expression was detected by immunohistochemical staining of freeze-dried cryofixed livers. Positive controls for immunohistochemistry included tumors grown by injecting athymic nude mice with cell lines having known oncogene expression. Livers from 15 DEN-exposed fish contained 178 altered foci and neoplasms; 48% of these lesions over-expressed Ras, Myc, Fos, p53 or epidermal growth factor receptor (EGFR). Raf overexpression was not detected. Myc overexpression was positively correlated (P < 0.05) with smaller hepatocyte size in both hepatocellular neoplasms and in altered foci. Increased EGFR expression occurred primarily in inflamed lesions. Increased Ras expression in hepatocellular neoplasms was correlated with anaplasia, gamma-glutamyltranspeptidase activity and lesions that contained mixed acinar and trabecular profiles. Accumulation of p53 occurred more often in neoplasms than in altered foci and correlated with unusual cytoplasmic vacuoles. In hepatocellular neoplasms, Fos overexpression was correlated with increased cell diameter, nuclear pleomorphism, and enlarged nucleoli. Only 1/14 biliary neoplasms overexpressed an oncoprotein (Myc). None of the changes in oncoprotein expression were correlated with cell proliferation (bromodeoxyuridine staining). Although several of the correlations found in mangrove rivulus also occur in mammals, the general relevance of some of our findings can be determined only after they are confirmed in other species.
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PMID:Oncogene expression in hepatic and biliary neoplasms of the fish Rivulus ocellatus marmoratus: correlation with histologic changes. 792 95

Microwave oven (mwo) is used to stimulate tissue fixation and to retrieve antigens damaged by fixation. Heavy metal salt solutions, water, and citric acid buffer (cab) have been suggested for this purpose. A serie of tumors treated with cab and phosphate-buffered saline (pbs) with mwo were studied immunohistochemically with 24 antibodies. Controls were treated in the same way, except for microwaving. The antibodies were directed against antigens of the following tumors: breast and prostate carcinoma, carcinoid, lymphoma and melanoma. The results showed that cab enhanced the immunoreactivity of the following antigens: estrogen receptors (AMAC), progesterone receptors (Novocastra), HMB45, vimentin, leukocyte common antigen, PCNA, p53, MIB-1 (Ki-67) and prostatic specific antigen. The antigens that did not improve their immunoreactivity, when compared with the control series were: factor VIII, keratin, Leu 22, L26, neuron-specific enolase, CEA, chromogranin, HBME-1, smooth muscle actin and EMA. Microwaving equally improved protein S100 and desmin either with cab or pbs. The only antigen that improved with pbs was actin. The results with B72.3 and NKI/C3 were poor and not reliable. In conclusion microwaving with cab enhances the immunoreactivity of the antibodies mentioned above leading to an increase in sensibility without loosing specificity.
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PMID:[Antigen retrieval by microwave oven with buffer of citric acid]. 799 28

An elevated risk of bladder cancer has been reported in the endemic region of 'black foot disease' on the southwest coast of Taiwan and may be related to high arsenic levels in artesian well water. Thirteen urothelial tumors from this endemic region were examined for mutations in exons 5-8 of the p53 gene to identify the effects of possible exogenous factors at the DNA level. DNA was extracted from archival tissue after microdissection of tumors and analyzed by PCR-SSCP (polymerase chain reaction-based single strand conformation polymorphism), followed by direct sequencing. Eight cases (62%) showed mutations and 9 of the 10 point mutations observed were transitions. The type and position of the mutations were not significantly different when compared with the spectra of p53 mutations previously reported for transitional cell carcinomas (TCCs). However, two of the mutations were CGC-->CAC base changes at codon 175, a mutational hotspot for many tumor types but previously unreported in TCCs except in cases associated with inflammatory agents. Three of the tumors examined were found to contain double mutations, a relatively rare mutagenic event in human cancers. Our results suggest that the agents responsible for the high risk of bladder cancer in the black foot disease region may operate through an inflammation-based mechanism which increases the amount of DNA damage per mutagenic event.
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PMID:Mutational spectrum in the p53 gene in bladder tumors from the endemic area of black foot disease in Taiwan. 802 Jan 37


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