PubMed Health⌕ Search

Biomedical subjects

E Boschetti

Publications and source records attributed to E Boschetti.

At least 91 records · Page 5Linked to original sources
PubMed1984

Culture of chondrocytes in medium supplemented with fetal calf serum or a serum substitute: Ultroser G.

Fetal calf serum and a serum substitute, Ultroser G, were compared for their effects on the growth curves, clonal growth and cell cycle progression of rabbit chondrocytes in primary culture and during at least three cell passages and included a screen for the maintenance of cartilage-like differentiation i.e. the presence of type II collagen. Proliferation was also compared with another serum substitute, Nu-Serum. Ultroser G is shown to be equivalent to fetal calf serum as far as chondrocyte proliferation is concerned, clonal growth is improved and biosynthesis of type II collagen is maintained in primary culture.

Animals↗
PubMed1983

Cell affinity chromatography with ligands immobilized through cleavable mercury-sulfur bonds.

A new methodology for cell separation by affinity chromatography is described. We have conjugated the organomercurial mersalyl to trisacryl beads bearing primary amino groups. Thiolated ligands can be immobilized on this matrix through cleavable Hg-S bonds. Two model studies of cell separation are reported: (i) concanavalin A thiolated with N-succinimidyl-3-(2-pyridyldithio)-propionate and immobilized on mersalyl-trisacryl; mouse thymocytes bound to Con A-mersalyl-trisacryl were eluted from the support by short thiol treatment which preserved cell viability; (ii) anti-dinitrophenyl antibodies modified with S-acetyl-mercaptosuccinic anhydride and immobilized on mersalyl-trisacryl; sheep erythrocytes, previously labelled with trinitrobenzene sulfonic acid, bound to this support and were easily recovered by thiol treatment without hemolysis. This methodology should overcome difficulties frequently encountered in cell affinity chromatography. Cell support multivalent interactions or high affinity of cell-ligand bindings often require drastic elution conditions which prevent viable cell recovery.

Animals↗
PubMed1982

Interactions between calmodulin and immobilized phenothiazines.

The ability of a number of antipsychotic drugs such as phenothiazines to bind to calmodulin with high affinity in a calcium-dependent manner was applied to the study of the nature of their interactions with calmodulin. Thus, a series of phenothiazine derivatives and analogues were immobilized on agarose and examined for their binding characteristics to calmodulin. The binding of calmodulin to fluphenazine, perphenazine and 7-aminotriflupromazine involved on the one hand non-specific electrostatic interactions which are abolished by increasing the eluent salt concentration, and on the other hand, Ca2+-dependent interactions which are reversed by EGTA addition. However, the Ca2+-dependent binding of calmodulin was less specific with phenothiazine structural analogues (neutral Red, diphenylamine) and was suppressed with other phenothiazine derivatives (thionine, Azure C, Toluidine Blue) or analogues (Brilliant Cresyl Blue). It is suggested that the calcium-dependent interactions between calmodulin and drugs involve a charge transfer pi-pi interaction which may be modulated by the electron donor-acceptor properties of the substituents of the aromatic ring. Affinity chromatography using immobilized fluphenazine was also used as the basis for the purification of calmodulin from a number of tissues in a rapid one-step procedure.

Animals↗
PubMed1982

[Separation of albumin and IgG by direct chromatographic fractionation of human plasma on DEAE and CM-trisacryl M].

We described a continuous chromatographic process using gel-filtration on Ultrogel AcA 202 and ion exchange chromatography on DEAE and CM-Trisacryl M. The human plasma cryosupernatant is firstly desalted on Ultrogel AcA 202 equilibrated in 0.025 M Tris-HCl buffer pH 8.8. containing 0.035 M NaCl and, then, applied to a column of DEAE-Trisacryl M. By these steps, we have obtained following results: - the IgG are not adsorbed and obtained directly with a minimal purity of 99.5%; - a fraction containing alpha2 and beta2 globulin (such as transferrin is removed by elution with 0.025 M Tris-HCl, buffer pH 8.5 containing 0.075 M Na Cl; - crude albumin (purity of 70%) is eluted with 0.025 M Tris-HCl, buffer pH 7.5 containing 0.15 M NaCl. The prepurified albumin is equilibrated on Ultrogel AcA 202 (0.04 M acetate buffer, pH 4.2) and, then, applied to a CM-Trisacryl M column: - the non adsorbed fraction contains alpha and beta-globulins; - a 98% pure albumin is removed by elution with 0.1 M acetate buffer pH 5; - the more adsorbed protein fraction are removed by elution with 0.1 M acetate buffer, pH 4.2. All the chromatographic steps can be completed within 7 h. The purity of the final products fulfills the Pharmacopeia requirements. The characteristics of this plasma protein fractionation process are discussed related to the properties of the new ion exchangers Trisacryl.

Acrylic Resins↗
PubMed1981

[Valve of a freeze-dried gelatin-agarose combination in selective extraction of fibronectin from human plasma].

We report here a simple procedure for the isolation of human plasma fibronectin by affinity adsorption on a new lyophilized adsorbent which is obtained by mixing and polymerizing agarose with gelatin. This method permits to obtain fibronectin and a fibronectin-depleted plasma without dilution. The yield of fibronectin is about 20 to 25 per cent. Fibronectin was identified by cross-reactions against specific antibodies. Its purity (greater than or equal to 99 per cent) was controlled by immunoelectrophoresis and SDS-PAGE. Furthermore, its biological activity was demonstrated by a spreading test performed on BHK cells. Such a test can be used to determine the specific activity of extracted fibronectin considering that the number of spread cells placed in presence of exogenous fibronectin (5 microgram/ml of culture medium) was 4.5 to 5 fold-superior to the control, after 30 minutes of incubation at 37 degrees C.

Antibody Specificity↗
PubMed1979

Acute and chronic effects of nifedipine on plasma renin activity and plasma adrenaline and noradrenaline in controls and hypertensive patients.

1. Nifedipine, a calcium antagonist drug, was given sublingually (10 mg) to seven normal subjects and 19 patients with essential hypertension. In addition, 12 of the hypertensive subjects then received nifedipine (10 mg thrice daily) for 3 weeks. 2. Sublingual administration of nifedipine in hypertensive patients induced a prompt and sustained reduction of blood pressure, without a significant increase of heart rate; in normotensive subjects blood pressure did not change, and heart rate was significantly increased. After chronic treatment, blood pressure remained reduced and heart rate did not rise. 3. Plasma catecholamines and plasma renin activity increased significantly in normotensive subjects after acute administration. 4. After both acute and chronic administration, only plasma noradrenaline was significantly increased in hypertensive patients; in long-term treatment, it was increased in both the lying and standing positions. 5. Nifedipine is an active antihypertensive drug, which may induce some degree of sympathetic activation.

Adult↗
PubMed1979

Properties of succinylated wheat-germ agglutinin.

The physicochemical and binding properties of succinylated wheat germ agglutinin are described in comparison with these of unmodified wheat germ agglutinin. Succinylated wheat germ agglutinin is an acidic protein with a pI of 4.0 +/- 0.2 while the native lectin is basic, pI of 8.5. The solubility of succinylated wheat germ agglutinin is about 100 times higher than that of the unmodified lectin at neutral pH. Both lectins are dimeric at pH down to 5, and the dissociation occurs at pH lower than 4.5. The binding of oligosaccharides of N-acetylglucosamine to both lectins is very similar on the basis of fluorescence and phosphorescence studies. The minimal concentration required to agglutinate rabbit red blood cells is about 2 microgram/ml with both lectins and the concentrations of N-acetylglucosamine and di-N-acetylchitobiose which inhibit agglutination are similar with both lectins. The number of succinylated wheat germ agglutinin molecules bound to the surface of mouse thymocytes was ten times lower than that of the unmodified lectin although the apparent binding constant was only slightly different between the two lectins. The dramatic decrease of the apparent number of cell surface receptors upon succinylation of the lectin is discussed on the basis of the decrease of the isoelectric point and of the acidic properties of the cell surface.

Fluoresceins↗