Biomedical subjects

V Calderone

Publications and source records attributed to V Calderone.

24 records · Page 2Linked to original sources

PubMed1997

The unusual amino acid triplet Asn-Ile-Cys is a glycosylation consensus site in human alpha-lactalbumin.

Human alpha-lactalbumin has not been described as a glycoprotein, despite the fact that several alpha-lactalbumins of both ruminant and nonruminant species are known to be glycosylated. In all these species the glycosylation site is the 45Asn in the usual triplet 45Asn-Gly/Gln-47Ser. We have found that human alpha-lactalbumin is glycosylated and the glycosylation site has been determined by protein sequencing and mass spectrometry. We report an unusual glycosylation site at 71Asn in the triplet 71Asn-Ile-73Cys, which is conserved in all known alpha-lactalbumins except red-necked wallaby. That a relatively small proportion of the protein is glycosylated (about 1%) may reflect the importance of this region of the protein sequence to the molten globule state of alpha-lactalbumin.

Amino Acid Sequence↗

PubMed1996

Amino acid sequence and crystal structure of buffalo alpha-lactalbumin.

Isolation, purification, amino acid sequence determination and X-ray crystal structure of buffalo alpha-lactalbumin were performed in order to gain further knowledge of the molecular basis of alpha-lactalbumin in the lactose synthase complex. The deduced amino acid sequence differs at one position from the bovine alpha-lactalbumin sequence (at position 17). The refined crystal structure at 2.3 A is very similar to those previously reported for human and baboon alpha-lactalbumins. However, a portion of the molecule (residues 105-109) exhibits different conformation. It forms a 'flexible loop', and appears to be a functionally important region in forming the lactose synthase complex.

Amino Acid Sequence↗

PubMed1996

A modified aortic multiple-ring preparation for functional studies.

A comparison is made of four rat aortic preparations, that is, single ring, spiral strip, zig-zag strip, and multiple-ring, on the basis of the responses to norepinephrine (NE) and acetylcholine (ACh). The single ring preparation was suitable under isometric, but not under isotonic conditions, because of the small isotonic tension which developed in response to the contractile agonist. The spiral and the zig-zag strips showed a discontinuity in the relaxant activity of the ACh, probably because of the removal, or not, of the endothelium from the preparation. The reproducibility of both contracturant and relaxing responses in the multiple-ring preparation makes this the most suitable of all four for the study of vasoactive drugs.

Acetylcholine↗

PubMed1996

Human milk proteins may interfere in ELISA measurements of bovine beta-lactoglobulin in human milk.

It is widely believed that cow's milk proteins ingested by the mother, in particular beta-lactoglobulin (beta-LG), can pass into breast milk and thus sensitize predisposed infants. However, studies to evaluate bovine beta-LG in human milk have given conflicting results. The aim of this study was to analyse the correlation between the amount of cow's milk in the mother's diet and the presence of bovine beta-LG in breast milk. Human milk samples from 14 healthy non-atopic women on diets with different cow's milk contents were examined. The total concentration of bovine beta-LG or beta-LG immuno-like proteins (beta-LGIP) was determined by enzyme-linked immunosorbent assay (ELISA). Two separation procedures utilizing ELISA plates and an affinity chromatography column were set up to identify the human whey components recognized by the anti-beta-LG antibodies. beta-LGIP reactivities of milk from three groups on different diets were not significantly different. After splitting the antigen-antibody complexes, three main protein components, human lactoferrin, human beta-casein and human alpha-lactalbumin, were identified. This study would suggest that, at least in healthy subjects, false-positive results in ELISA determinations of bovine beta-LG in human milk might be due to cross-reactions between polyclonal antibodies and different protein antigens.

Adult↗

PubMedDate not supplied

5-(4'-Substituted-2'-nitroanilino)-1,2,3-triazoles as new potential potassium channel activators. I.

By the hypothesised correlation with the large conductance Ca(++)-activated potassium channel (BK(Ca)) openers NS 004 and NS 1619, bearing a benzimidazolone ring, a series of new 5-(4'-substituted-2'-nitroanilino)-1,2,3-triazoles were synthesised and tested on in vitro isolated vascular preparation. The compounds were prepared starting from the appropriately substituted 2-nitro-phenylazides by 1,3-dipolar cycloaddition reaction to cyanoacetamide and following Dimroth isomerisation of the corresponding 1-arylsubstituted-5-amino-1,2,3-triazoles. The analogous 5-(4'-substituted-2'-amino-anilino)-1,2,3-triazoles were also prepared to assess the role of the nitro group in the pharmacophoric model. Almost all the nitro compounds showed a vasorelaxant activity on endothelium-denuded rat aortic rings with a potency comparable to that recorded for the reference compound NS 1619. Such a vasorelaxing activity was significantly reduced by the increase of the level of membrane depolarisation and by the potassium channel blocker 4-aminopyridine with a pharmacodynamic behaviour consistent with a potassium channel activation.

Animals↗

PubMedDate not supplied

Synthesis and evaluation of antihypertensive activity of 1,8-naphthyridine derivatives. Part X.

A series of 4-(N-methylencycloalkylamino)-1,8-naphthyridine derivatives variously substituted in positions 2 and 7 were synthesized and pharmacologically investigated for possible antihypertensive activity. These compounds were tested to determine a possible vasodilator mechanism of action. Compounds 22, 23, 27-29, 47 and 48 showed satisfactory levels of potency (pIC(50)>5), which in one case (compound 23) reached a really interesting value (pIC(50) 6.92). Furthermore, for some selected compounds (19, 22, 23, 26, 28, 29, 47), the vasorelaxing activity was also evaluated in the presence of the guanylate cyclase blocker ODQ or of the adenylate cyclase blocker SQ 22536, and some of these can be considered as possible guanylate-cyclase inhibitors. Finally, compounds 19, 22 and 23 were also tested in the presence of the ATP-sensitive potassium channel blocker glybenclamide and seem to possess activating properties on these potassium channels.

Animals↗