Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Critical steps in the methodology of mutation analysis on routinely fixed, paraffin-embedded samples have been evaluated, including extraction and purification of DNA, amplification of gene fragments in various sizes, and screening for mutations. The DNA was extracted from tissue sections with proteinase K, using various procedures, and purified. The mutation cluster region of the APC gene was amplified with polymerase chain reaction to generate either two large or four small overlapping DNA fragments. The GC-clamped fragments were screened for mutations with temperature gradient gel electrophoresis, and mutations were identified with sequencing. The DNA was easily amplified as large fragments from fresh or unfixed-frozen samples. However, DNA amplification of large fragments from archival samples was successful in only 40 of the 114 tumor specimens analyzed (35%). Prolonged extraction, either at 55 degrees C or at 37 degrees C, gave no better results. Polymerase chain reaction of smaller fragments, with sizes between 200 and 270 base pairs (bp), was successful for 97% of the amplification reactions when using DNA that was purified with silica. Screening with temperature gradient gel electrophoresis was reproducible and sensitive with a detection limit of 5% mutated DNA in the presence of an excess of wild-type DNA.
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PMID:Optimizing the APC gene mutation analysis in archival colorectal tumor tissue. 1040 88

Cryptococcosis is a leading cause of death among individuals with compromised T cell function. Soluble Cryptococcus neoformans mannoproteins (MP) have emerged as promising vaccine candidates due to their capacity to elicit delayed-type hypersensitivity and Th type 1-like cytokines, both critical to the clearance of this pathogenic yeast. In this study, the mechanisms responsible for the potent immunostimulatory properties of MP were explored. Using Chinese hamster ovary cells expressing human macrophage mannose receptor (MMR), we determined that MP is a MMR ligand. Functionally, competitive blockade of multilectin mannose receptors (MR) on APCs diminished MP-dependent stimulation of primary T cells from immunized mice and the MP-reactive CD4(+) T cell hybridoma, P1D6, by 72 and 99%, respectively. Removal of O-linked saccharides from MP by beta-elimination inhibited MP-dependent stimulation of P1D6 and primary T cells by 89 and 90%, respectively. In addition, MP-dependent stimulation of P1D6 was abrogated after digestion with proteinase K, suggesting the protein core of MP contributed the antigenic moiety presented by APC. Stimulation of P1D6 by MP also was abolished using APC obtained from invariant chain-deficient mice, demonstrating Ag presentation was MHC class II restricted. Our data suggest that MP is a ligand for the MMR and that T cell stimulation is functionally inhibited either by competitive blockade of MR or by removal of carbohydrate residues critical for recognition. The demonstration that efficient T cell responses to MP require recognition of terminal mannose groups by MMR provides both a molecular basis for the immunogenicity of cryptococcal MP and support for vaccination strategies that target MR.
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PMID:Optimal T cell responses to Cryptococcus neoformans mannoprotein are dependent on recognition of conjugated carbohydrates by mannose receptors. 1188 57

Spectral changes in fluorescence of phycobilisomes (PBS) of A. variabilis treated with proteinase K were studied at room and liquid nitrogen temperature. In control PBS, the relative yield of 77 K fluorescence of F686 was very high, and those of F655 and F666 were low. In PBS treated with proteinase K for less than 1 h, F686 decreased, and F655 and F666 increased. In PBS treated with proteinase K for 2 h, F655 was the main peak of fluorescence emission, F686 was the second peak, the fluorescence emission peak of F666 disappeared. In PBS treated with proteinase K for more than 8 h, F655 showed only one fluorescence emission peak.We suggested that phycobiliporteins in the PBS of A. variabilis constitute an energy transfer chain, shown as follows:{fx91-1}The linkages between APC and APC-B, C-PC and APC, and C-PC and APC-B had different sensitivity towards proteinase K.
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PMID:Effects of proteinase K on the energy transfer between phycobiliproteins in phycobilisomes. 2444 16