Biomedical subjects

G Zoppetti

Publications and source records attributed to G Zoppetti.

At least 37 records · Page 2Linked to original sources

PubMed1986

Retention of antilipemic activity by periodate-oxidized non-anticoagulant heparins.

Heparin preparations with different anticoagulant and antilipemic (fat-clearing) activities were oxidized with periodate under conditions of cleavage of all the C(2)-C(3) bonds of non-sulfated uronic acid residues, while preserving the original molecular weight of the polysaccharide. Periodate-oxidised heparins (oxyheparins, O-HEP) and the corresponding borohydride-reduced products (reduced oxyheparins, RO-HEP) were compared with the original heparins for their content in trisulfated disaccharide sequences (as determined by 13C-nuclear magnetic resonance) and in active sites for antithrombin-III (as determined indirectly by affinity chromatography), and for their anticoagulant and antilipemic (lipoprotein lipase-releasing) activities. The drop of anticoagulant activity induced by periodate oxidation was paralleled by a substantial decrease of affinity for antithrombin, and is thought to arise from glycol splitting at the level of the D-glucuronic acid residue that is part of the active site for antithrombin. The trisulfated disaccharide sequences and the associated antilipemic activities were substantially unaffected by periodate oxidation. The residual anticoagulant activity of periodate-oxidized heparins obtained from preparations - such as those from beef lung - rich in trisulfated disaccharide sequences is discussed in terms of the influence of charge density on heparin-protease interactions not mediated by antithrombin.

Animals↗

PubMed1984

Serum autoantibodies and thyroid lymphocytic infiltration in endemic goitre.

Patients with thyroid diseases from areas of endemic goitre in Northern Italy were examined for thyroid antibodies by passive haemoagglutination. Of 40 schoolboys with goitre only one had thyroid antibodies (AT) in the blood. Among 182 adults with grade 1-2 goitre, examined within an area of low endemia, the frequency of AT was 7%, not significantly different from that found in the 286 persons with thyroid 'O' living in the same area. Among 181 adults with grade 2-3 goitre, examined within an area of serious endemia, the frequency of AT was 16%; the percentage went up to 24% in 144 patients operated on for goitre. AT frequency was 36% in 87 patients with toxic goitre, more than 70% in 97 patients with Graves' disease and 17% in 60 patients with cancer of the thyroid. AT occurred three times more frequently in women than in men. Microsomal antibodies were more frequently detected than anti-thyroglobulin antibodies: the opposite was true in thyroid cancer. Lymphocytic infiltration (IL) of the gland was observed in 45% of the 464 simple goitres and in 52% of the 60 cancers of the thyroid: it was more frequent and intense in women. Among the 144 patients operated on for goitre the frequency and the titre of AT progressed in parallel with the intensity of the lymphocytic infiltration. Patients with a greater lymphocytic infiltration and higher AT had a higher TSH. Multinodular non-toxic goitre and autoimmune lymphocytic thyroiditis can be present in the same thyroid gland and the clinical expression will depend on which condition predominates.

Adolescent↗

PubMed1983

Correlation between structure, fat-clearing and anticoagulant properties of heparins and heparan sulphates.

Heparins and heparan sulphates from different organs, of high purity by accepted criteria, were characterized by chemical and physical (including electrophoretic and 13C-NMR spectroscopic) methods. The fat-clearing activity of these preparations was shown to be correlated with their content of the trisulphated disaccharide units I2S-ANS,6S (L-iduronic acid 2-O-sulphate-N-sulphated D-glucosamino 6-O sulphate). Species with low anti-lipemic activity contained significant proportions (greater than or equal to 30%) of nonsulphated uronic acids (especially D-glucuronic acid), and of D-glucosamino residues undersulphated at C-6, these latter residues being partially N-acetylated. Heparins from beef lung and sheep mucosa, predominantly consisting of trisulphated disaccharide units, displayed consistently higher antilipemic activity than the more heterogeneous pig mucosal heparins. The anticoagulant activity (as determined by the U.S.P., APTT and anti-Xa tests) was not a simple function of the measured physicochemical parameters. Trends were confirmed for pig mucosal heparins being more anticoagulant than beef lung preparations, and low molecular weight (usually undersulphated) species being more active in the anti-Xa test than in the U.S.P. and APTT tests.

Amino Acids↗

PubMed1981

The structure of heparin oligosaccharide fragments with high anti-(factor Xa) activity containing the minimal antithrombin III-binding sequence. Chemical and 13C nuclear-magnetic-resonance studies.

The chemical composition and the 13C n.m.r. spectra of heparin oligosaccharides (essentially octasaccharides), having high affinity for antithrombin III and high anti-(Factor Xa) activity, prepared by three independent approaches (extraction, partial deaminative cleavage with HNO2 and partial depolymerization with bacterial heparinase), leading to different terminal residues, have been studied and compared with those of the corresponding inactive species. Combined wit chemical data, the spectra of the active oligosaccharides and of their fragmentation products afforded information on composition and sequence. The three types of active oligosaccharides were shown to have the common hexasaccharide core I-Aa-G-As*-Is-As, where I and alpha-L-idopyranosyl-uronic acid, Aa = 2-acetamido-2-deoxy-alpha-D-glucopyranose, G = beta-D-glucopyranosyl-uronic acid, Is = alpha-L-idopyranosyluronic acid 2-O-sulphate, As = 2-deoxy-2-sulphamino-alpha-D-glucopyranose 6-O-sulphate. The fourth residue (As*) is an unusually substituted amino sugar resistant to mild deamination. The 13C spectra of the active species are characterized by signals from the above atypical amino sugar, the most evident of which is at 57.7 p.p.m. These signals, compared with those of appropriate synthetic model compounds, are compatible with the recently proposed 3-O-sulphation of the residue As* [Lindahl, Bäckström, Thunberg & Leder (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 6551-6555].

Animals↗

PubMed1974