Disease relevance of MRAP

• CONCLUSION: Multiple single sections Turbo FLASH MRAP may be a valuable adjunct for pre-operative detection of malignant hepatic neoplasms [1].
• RESULTS: The overall sensitivity in detecting liver metastases was 97% with MRAP and 93% with CTAP (p > 0.05, not significant [n.s.]) [2].
• The MR images of 24 patients with 39 hepatocellular carcinomas and 18 benign hepatocellular nodules examined with dynamic MR imaging and MRAP within a 14-day interval were retrospectively reviewed [3].
• The purpose of this study was to document the additional value of MR imaging during arterial portography (MRAP) in patients examined with intravenous contrast-enhanced dynamic MR imaging for the assessment of focal lesions in patients with cirrhosis or chronic viral hepatitis [3].
• If organizational difficulties of MRAP can be overcome, MRAP could be considered instead of CTAP in the preoperative invasive evaluation of metastatic liver disease [2].

Psychiatry related information on MRAP

• In contrast, cells expressing B27 with the single substitution of F for H at position 9 (B27.H9F) retained their permissiveness [4].

High impact information on MRAP

• 1. We identified mutations in a gene encoding a 19-kDa single-transmembrane domain protein, now known as melanocortin 2 receptor accessory protein (MRAP) [5].
• We show that MRAP interacts with MC2R and may have a role in the trafficking of MC2R from the endoplasmic reticulum to the cell surface [5].
• Letter: Are homozygotes for HLA B27 more susceptible to ankylosing spondylitis [6]?
• In adults, mutations in a dominant and highly conserved B27-restricted Gag CTL epitope lead to loss of recognition and disease progression [7].
• Evidence for a specific B27-associated cell surface marker on lymphocytes of patients with ankylosing spondylitis [8].

Chemical compound and disease context of MRAP

• The results are discussed in relation to the potential involvement of homocysteine-specific CTL in ankylosing spondylitis and reactive arthritis, both of which are related to bacterial infections, associated with HLA B27, and considered to be autoimmune diseases [9].
• CONCLUSION: Infliximab proved to be a powerful therapeutic agent in acute HLA B27-associated uveitis and may therefore be a future alternative or supplement to steroid treatment [10].
• A patient suffering from burns was treated with gentamicin: subsequently, a 'methicillin-resistant' strain of Staphylococcus aureus (B27), was isolated which was highly resistant to this antibiotic and all other aminoglycosides [11].
• Levamisole-induced neutropenia and agranulocytosis: association with HLA B27 leukocyte agglutinating and lymphocytotoxic antibodies [12].
• B27 was associated with SI and uveitis in Pima males, but no association was demonstrated between B27 and SI in Pima females [13].

Biological context of MRAP

• Whether the novel MRAP mutation described by us is associated with a particularly severe phenotype remains to be investigated [14].
• Mean RAP (MRAP) was measured by ophthalmodynamometry (ODM) and was expressed as a ratio of the mean systemic arterial blood pressure (i.e., MRAP/MSAP) [15].
• Experiments with hybrid exons created from the HLA-B27 and HLA-A2 genes yielded results consistent with the mapping of the ME1 epitope to the B27 alpha 1 domain [16].
• The other gene, also carried on the sixth chromosome and, in the first family, marked by the HLA A11, B27, CW2 haplotype might result in an increased absorption of dietary iron [17].
• These observations suggest an unappreciated mechanism for autoimmunity that may operate in the B27-associated spondyloarthropathies involving peptides bound to and derived from histocompatibility alleles [18].

Anatomical context of MRAP

• Whereas the function of Falp is currently unclear, its tissue specific expression and the responsiveness to insulin suggest that Falp might be involved in a process specifically restricted to adipose tissue function, such as vesicular transport and protein secretion [19].
• SUBJECTS AND METHODS: In addition to static T1- and T2-weighted MR imaging, MRAP was performed immediately after hepatic angiography through contrast material injection into intraarterially placed catheters (superior mesenteric or splenic artery) in 21 patients with nodular hepatocellular carcinoma [20].
• The B27 molecule in this family proved to be the B2702 subtype on isoelectric focusing gels, appearing in exactly the same position as B2702 from other cell lines that did present the peptide [21].
• We first noted that EBV-specific CTL clones, whether from B27.05-, B27.02-, or B27.04-positive donors, were largely subtype-specific in their restriction, recognizing only EBV-transformed B cell lines of the relevant B27 subtype [22].
• These results suggest that the expression of HLA-B27 in bone marrow-derived cells alone is sufficient for the development of B27-associated disease, and that disease transfer requires engraftment of a bone marrow precursor cell for which mature cells in spleen or in lymph node cannot substitute [23].

Associations of MRAP with chemical compounds

• MRAP followed with gadolinium-enhanced dynamic T1-weighted 3D FLASH [2].
• Moreover, crosslinking native or truncated A2 or B27 induced IL-2 production upon co-stimulation with phorbol myristate acetate [24].
• By a series of sequential immunoprecipitation experiments, X was shown to be a "public" antigenic determinant distinct from the "private" determinants B7, Bw22, B27, and B40, but present on the same 44,000-dalton glycoprotein molecules [25].
• Normal luminal bacteria predictably and uniformly induce chronic colonic, gastric and systemic inflammation in B27 transgenic F344 rats, but all bacterial species do not have equal activities [26].
• Levamisole-induced adverse reactions in HLA B27-positive rheumatoid arthritis [27].

Other interactions of MRAP

• The MRAP protein appears to function in the trafficking and cell surface expression of the ACTH receptor, and might indicate the existence of more widespread G-protein-coupled receptor trafficking mechanisms [28].
• The sensitivity for detection of hepatocellular carcinoma was higher for MRAP (94%) than for CTAP (83%); however, the difference was not statistically significant (p > .05) [20].
• Clearly, other genes that cause FGD remain to be discovered, and further work is required on the functions of MRAP and ALADIN in the expectation that they will provide insights into essential biological processes and perhaps identify key therapeutic strategies and targets for these diseases [29].

Analytical, diagnostic and therapeutic context of MRAP

• Magnetic resonance imaging during arterial portography (MRAP) was performed by the authors in a selected group of 12 patients with hepatic lesions [30].
• The mean MRAP/MSAP for combined Groups I, II, and III with ICA occlusion proximal to the OA was significantly lower than both the control group (P = 0.0001) and the combined Groups IV, V, VI, and VII with occlusive lesions distal to the OA (P = 0.0001) [15].
• Nontumoral perfusion abnormalities are seen frequently on MRAP examination [31].
• The sensitivity and specificity of MRAP for lesion detection and the differential diagnosis of hepatocellular carcinoma were compared with the sensitivity and specificity of CTAP [20].
• Findings of MRAP were compared with surgical specimen and intra-operative ultrasonography (US) [1].

References