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Biomedical subjects

M Vuento

Publications and source records attributed to M Vuento.

47 records · Page 3Linked to original sources
PubMed1979

Purification of fibronectin from human plasma by affinity chromatography under non-denaturing conditions.

Fibronectin was purified from human plasma by affinity chromatography under nondenaturing conditions. The method was based on the previously known binding of fibronectin to gelatin. The novel features of our method are the use of arginine in the elution of fibronectin from immobilized gelatin [Vuento & Vaheri (1978) Biochem. J. 175, 333-336] and the use of arginine-agarose as second affinity step. The purified protein was homogeneous as judged by polyacrylamide-gel electrophoresis, analytical ultracentrifugation and two-dimensional immunoelectrophoresis. The yield was 60%. We propose that the method would be useful in preparation of fibronectin for studies on its biological activities, where it is important that the protein is obtained in a native state.

Amino Acids↗
PubMed1979

Hemagglutinin activity of human plasma fibronectin.

Purified human plasma fibronectin at concentrations of about 30 microgram/ml was found to agglutinate trypsin-treated erythrocytes from certain species. The hemagglutination reaction was inhibited by specific antibodies to fibronectin, by relatively low concentrations of polyamines and by higher concentrations of basic amino acids and nonacetylated amino sugars. The divalent cations Ca2+ and Mg2+ and the chelating agent ethylenediaminetetraacetate did not affect the reaction. None of the neutral amino acids, neutral sugars or polyanions tested was inhibitory. The results imply that plasma fibronectin is capable of interacting with cell surfaces and support the idea of a similarity between cellular and plasma fibronectins.

Amino Acids↗
PubMed1978

Dissociation of fibronectin from gelatin-agarose by amino compounds.

Soluble fibronectin of human plasma was specifically dissociated at neutral pH from gelatin-agarose by several cationic amino compounds, notably the polyamines spermine, spermidine and putrescine, the basic amino acid arginine, and amino sugars. The neutral and acidic amino acids and the N-acetylated derivatives of amino sugars tested were ineffective. Gel-filtration experiments demonstrated that [14C]spermidine bound to fibronectin but not to gelatin.

Amino Acids↗
PubMed1976

Isolation from human gastric juice of an antigen closely related to the carcinoembryonic antigen.

A carcinoembryonic antigen-like antigen(s) (CELIA) was isolated from normal human gastric jucie by immunoadsorbents and gel chromatography. The isolated CELIA reacted identically to CEA in immunodiffusion testa against anti-CEA and anti-CELIA. Other experiments suggested subtle differences between CELIA and CEA. Two out of six CELIA preparations tested in immunodiffusion did not react in a completely identical manner with CEA.In gel filtration, CELIA eluted slightly after CEA. Absorption of anti-CEA with CELIA resulted in antisera with greatly reduced reactivity to CELIA, but retained anti-CEA activity. Such antisera may be helpful in attempts to increase the cancer specificity of the CEA test.

Antigens↗
PubMed1976

Monkey antisera with increased specificity to carcino-embryonic antigen (CEA).

Three Macaca irus monkeys were immunized with purified human CEA. One received unmodified CEA and two were immunized with haptenated (4-hydroxy-5-iodo-3-nitrophenyl acetyl) CEA. All three monkeys formed precipitating antibodies to CEA. The antisera did not precipitate the CEA-related normal glycoprotein antigen (NCA). In contrast, CEA-immunized rabbits, sheep and goats invariably form antibodies against NCA. Radio-immunoassays showed the monkey antisera to contain trace amounts of antibodies to NCA but the titers were about 10-1,000 times lower than those in rabbit and sheep sera with comparable anti-CEA titers. These results show that monkeys produce antibodies against CEA, but respond weakly to a normal, CEA-related antigen. The weak response to NCA suggests that monkeys may possess an NCA-related antigen. Antisera lacking reactivity to normal CEA-related antigens may be helpful in establishing a more specific diagnostic test for CEA.

Animals↗
PubMed1976

A monkey antigen crossreacting with carcinoembryonic antigen, CEA.

Normal monkey tissues were found to contain an antigen which crossreacts immunologically with the carcinoembryonic antigen (CEA) of the human digestive tract. The monkey antigen reacted with complete or partial identity to the normal crossreacting antigen (NCA) in humans when tested in immunodiffusion against anti-CEA or anti-NCA. Extracts of monkey tissues inhibited in radioimmunoassays measuring human NCA. It is possible that monkey foetuses and colonic tumours contain CEA.

Animals↗
PubMedDate not supplied

CEA and CEA-like activity in gastric cancer.

CEA activity was studied using a three-layer bridge immunoperoxidase method in paraffin-embedded histological sections of gastric mucosa from patients with gastric cancer and from normal asymptomatic subjects. In all cases gastric cancer cells showed CEA or CEA-like activity irrespective of the histological type of cancer. The activity was located mainly in cellular membranes, on the brush border or in apical parts of the cell cytoplasm. CEA activity could not be demonstrated in mucosa specimens from normal controls. These results indicate that the appearance of CEA or CEA-like substances is regularly associated with the malignant transformation of epithelial cells of the gastric mucosa.

Adenocarcinoma↗
PubMedDate not supplied

Effect of lectins and chemical modification on the hemagglutinin activity of human plasma fibronectin.

Purified human plasma fibronectin has been shown to agglutinate protease-treated red cells [Vuento, Hoppe-Seyler's Z. Physiol. Chem. 360, 1327-1333, (1979)]. The present report shows that the activity is inhibited by low concentrations of lectins and by macromolecular serum factors. Chemical modification of carboxyl groups of fibronectin strongly inhibited the activity, but modification of amino groups of guanidinium groups had little effect on the activity. The results suggest that fibronectin receptors on erythrocyte surface are carbohydrate-containing molecules. Humoral macromolecular factors may control the interaction of fibronectin with cell surfaces. Chemical modification studies indicate that the parts of the fibronectin molecule responsible for the hemagglutinin activity are different from those mediating the binding of fibronectin to collagen.

Animals↗