RESUMO
Antigen B (AgB), an immunodominant component of the cestode parasite Echinococcus granulosus, presents homology to and shares apparent structural similarities with helix-rich hydrophobic ligand binding proteins (HLBPs) from other cestodes. In order to investigate the fatty acid binding properties of AgB, two of its subunit components (rAgB8/1 and rAgB8/2) were expressed in Escherichia coli and purified, and the native antigen was purified from the hydatid cyst fluid by affinity chromatography using a monoclonal antibody raised against rAgB8/1. The interaction of the purified native and recombinant proteins with the fluorescent ligands DAUDA, ANS, DACA and 16-AP was investigated. The palmitic acid derived fluorescent ligand, 16-AP, showed the greatest enhancement in fluorescence when bound to native AgB or to its recombinant subunits, and the dissociation constants for 16-AP binding were determined. Surprisingly, in contrast to HLBPs from other cestodes, interactions with other fatty acids, including palmitic acid, caused an increase in fluorescence instead of competing with 16-AP. Our results suggest that AgB might have evolved different functions in the binding of hydrophobic compounds, dependent on cestode environment.
Assuntos
Ácidos Graxos/metabolismo , Proteínas de Helminto/química , Interações Hidrofóbicas e Hidrofílicas , Lipoproteínas/química , Animais , Anticorpos Anti-Helmínticos/imunologia , Anticorpos Monoclonais/imunologia , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Cestoides/química , Cestoides/metabolismo , Cromatografia de Afinidade , Líquido Cístico/metabolismo , Escherichia coli/genética , Ácidos Graxos/química , Proteínas de Helminto/imunologia , Proteínas de Helminto/metabolismo , Cinética , Ligantes , Lipoproteínas/imunologia , Lipoproteínas/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Espectrometria de FluorescênciaRESUMO
Tumor markers have been investigated in differentiation of benign and malignant tumors. We analyzed CA 125 and vascular endothelial growth factor (VEGF) levels in serum and cyst fluid in patients with epithelial ovarian tumors. Serum and tumor cyst fluid of 50 patients with ovarian epithelial tumors (7 malignant, 3 bordeline and 40 benign) were assayed for VEGF by ELISA and CA 125 levels by chemoluminescence. CA 125 serum levels were significantly higher in patients with malignant and borderline tumors than in patients with benign cysts (p = 0.0005). CA 125 cyst fluid contents were comparable for malignant, borderline and benign ovarian tumors (p = 0.39). Significantly higher levels of VEGF were present in cyst fluid for malignant and borderline tumors compared with benign cysts (p < 0.0001); however, serum levels of VEGF were similar among all patients (p = 0.25). The CA 125 serum levels correlated with matched VEGF cyst fluid levels (r = 0.44, p = 0.0015). Serum CA 125 and cystic VEGF were good methods to differentiate benign and malignant epithelial ovarian tumors. Patients with elevated intracystic VEGF levels presented significantly higher CA 125 serum levels, although the CA 125 intracystic content overlapped. The angiogenesis and enhancement of vascular permeability induced by VEGF represents a new hypothesis for the release of the CA 125 antigen into the circulation in patients with ovarian epithelial neoplasm.
Assuntos
Biomarcadores Tumorais/metabolismo , Antígeno Ca-125/metabolismo , Carcinoma/diagnóstico , Fatores de Crescimento Endotelial/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Linfocinas/metabolismo , Neoplasias Ovarianas/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/sangue , Antígeno Ca-125/sangue , Carcinoma/sangue , Líquido Cístico/metabolismo , Fatores de Crescimento Endotelial/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Medições Luminescentes , Linfocinas/sangue , Pessoa de Meia-Idade , Cistos Ovarianos/metabolismo , Neoplasias Ovarianas/sangue , Valor Preditivo dos Testes , Curva ROC , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Gross cystic breast disease (GCBD) is common in women, especially in the age range between 35 and the menopausal years. The present study examined the possible role of progesterone (Pg) in the chorionic gonadotropin (hCG) concentration in GCBD. The breast cyst fluids (BCFs) were drawn by fine needle aspiration between the sixth and the eighth day of the menstrual cycle and twenty days later. On the day of the first aspiration the patient began to take 100 mg of natural micronized Pg orally until the second aspiration. At both times blood samples were also taken. Determinations were done of both BCFs and blood sample using two fully automated chemiluminiscent enzyme immunometric assays. Pg has been demonstrated to induce a significant increment in hCG + free ss-hCG (median, range): 0.27 ng/ml, 0.12-6.24 vs. 1.92 ng/ml, 0.12-423.5; free ss-hCG: 0.11 ng/ml, 0.02-2.40 vs. 0.91 ng/ml, 0.02-58.40 in the BCFs, with no change in the circulating concentrations of the hormone. None of the sera studied presented levels of hCG + free ss-hCG or free ss-hCG above 0.5 ng/ml or 0.1 ng/ml, respectively. The occurrence of hCG or a derivative polypeptide in BCFs, when they are present in high concentrations suggests that this glycoprotein could be synthesized in situ and possibly involved in the pathogenesis of GCBD by the degree of differentiation of breast epithelial cells induced by the hormone.