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)

Recognition of viral Ag and of the envelope glycoprotein of HIV (gp120) in particular by human Th cells is critical in the immune response to the viral Ag which includes antibody production and generation of cytotoxic cells. Procedures to increase antigenicity of gp120 are highly desirable in a vaccine perspective. Therefore, to induce activation of gp120-specific T cells by a liminal dose of Ag we enhanced uptake of gp120 by exploiting the galactose receptors on APC. Terminal sialic acid residues were removed by neuraminidase treatment from the carbohydrate side chains of the heavily glycosylated gp120. Galactose residues were exposed and hence recognized by galactose receptors on APC. The experiments demonstrated that 1) human monocytes and dendritic cells, but not cells of the B lineage, bear galactose receptor; 2) galactose receptors are indeed involved because enhanced presentation is inhibited by galactose and acetylgalactosamine and competed for by other asialoglycoproteins; 3) galactose receptors mediate internalization of Ag in intracellular compartments that intersect the processing and presenting pathways, resulting in activation of specific T cells; 4) antigenicity of gp120 for specific T cells can be enhanced by the exposure of galactose residues.
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PMID:Galactose receptors and presentation of HIV envelope glycoprotein to specific human T cells. 131 6

The elimination of ethanol (ETOH) as a gas in human insensible perspiration (PAC) was investigated following the oral administration of 0.5 g/kg or 0.75 g/kg of alcohol. Simultaneous breath alcohol analysis (AAC) was also carried out for comparison purposes. To determine reproducibility, one subject experienced five trials at each dose over a period of six months, in addition to a single dose (0.5 g/kg) trial with five other subjects. All ETOH concentrations were determined by gas chromatography (GLC). A one-compartment open model with first order absorption and pseudo-zero-order elimination was used to compute the pharmacokinetic parameters. The average first order absorption rate constant (K alpha) and pseudo-zero-order elimination rate constant (beta) for ten trials in a single subject were: K alpha AAC = 1.60 h-1 and 1.39 h-1, beta AAC = 0.154 g/l/h and 0.192 g/l/h. K alpha PAC = 1.27 h-1 and 1.11 h-1, beta PAC = 0.109 g/l/h and 0.141 g/l/h for 0.5 g/kg and 0.75 g/kg ETOH, respectively. In all experiments, AAC was consistently higher than PAC during active absorption, with significantly higher (p less than 0.05) average peak concentration (Cmax) and shorter (p less than 0.05) average time to peak (tmax). However, during the later stages of elimination, AAC falls below PAC, with a significantly faster (p less than 0.05) elimination rate (beta). The data indicates that ETOH elimination via perspiration does not parallel the breath and that the pharmacokinetic parameters are significantly different.
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PMID:The pharmacokinetics of alcohol excretion in human perspiration. 407 88

Bovine and human protein C show high homology in the amino acids of their GLA domains (amino-terminal 44 residues), despite the about 10-fold higher membrane affinity of the human protein. A proposed membrane contact site and mechanism suggested that this difference was largely due to the presence of proline at position 10 of bovine protein C versus histidine at position 10 of human protein C [McDonald, J.F., Shah, A.M., Schwalbe, R.A., Kisiel, W., Dahlback, B., and Nelsestuen, G.L. (1997) Biochemistry, 36, 5120-5127]. This study examined the impact of replacing proline-10 in bovine protein C with histidine, and the reverse change in human protein C. In both cases, the protein containing proline-10 showed lower membrane affinity, about 10-fold lower for bovine protein C and 5-fold lower for human protein C. As expected, activated human protein C (hAPC) containing proline at position 10 showed 2.4-3.5-fold lower activity than wild type hAPC, depending on the assay used. Most interesting was that bovine APC containing histidine-10 displayed up to 15-fold higher activity than wild type bAPC. This demonstrated the ability to improve both membrane contact and activity by mutation. This general strategy should be applicable to other vitamin K-dependent proteins, providing opportunities to study function as well as to produce proteins that may find use as promoters and inhibitors of blood coagulation in pathological states.
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PMID:Enhancing the activity of protein C by mutagenesis to improve the membrane-binding site: studies related to proline-10. 944 Aug 75

We showed previously that dietary eicosapentaenoic acid [EPA, 20:5(n-3)] is antitumorigenic in the APC:(Min/+) mouse, a genetic model of intestinal tumorigenesis. Only a few studies have evaluated the effects of dietary fatty acids, including EPA and docosahexaenoic acid [DHA, 22:6(n-3)], in this animal model and none have evaluated the previously touted antitumorigenicity of alpha-linolenic acid [ALA, 18:3(n-3)], conjugated linoleic acid [CLA, 77% 18:2(n-7)], or gamma-linolenic acid [GLA, 18:3(n-6)]. Stearidonic acid [SDA, 18:4(n-3)], the Delta6-desaturase product of ALA, which is readily metabolized to EPA, has not been evaluated previously for antitumorigenic efficacy. This study was undertaken to evaluate the antitumorigenicity of these dietary fatty acids (ALA, SDA, EPA, DHA, CLA and GLA) compared with oleic acid [OA, 18:1(n-9)] at a level of 3 g/100 g in the diets of APC:(Min/+) mice and to determine whether any alterations in tumorigenesis correspond to alterations in prostaglandin biosynthesis. Tumor multiplicity was significantly lower by approximately 50% in mice fed SDA or EPA compared with controls, whereas less pronounced effects were observed in mice fed DHA (P: = 0.15). ALA, CLA and GLA were ineffective at the dose tested. Although lower tumor numbers coincided with significantly lower prostaglandin levels in SDA- and EPA-fed mice, ALA and DHA supplementation resulted in equally low prostaglandin levels, despite proving less efficacious with regard to tumor number. Prostaglandin levels did not differ significantly in the CLA and GLA groups compared with controls. These results suggest that SDA and EPA attenuate tumorigenesis in this model and that this effect may be related in part to alterations in prostaglandin biosynthesis.
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PMID:Highly unsaturated (n-3) fatty acids, but not alpha-linolenic, conjugated linoleic or gamma-linolenic acids, reduce tumorigenesis in Apc(Min/+) mice. 1101 69