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Biomedical subjects

A Rinaldi

Publications and source records attributed to A Rinaldi.

At least 109 records · Page 6Linked to original sources
PubMed1984

Circulating immune complexes containing IgG, IgA and IgM in patients with myocardial infarction: detection with C1qSP and anti C3SP.

Immunological reactions have been recognized in cardiac disease and immune complexes (ICs) have been suggested to be of pathogenetic significance in the occurrence of post-myocardial infarction syndromes. ICs of IgA, IgG, IgM class have been detected in myocardial infarction utilizing a C1qSP and an anti C3 assay. A poor concordance was found between the two methods. Early pericarditis was found to be associated with the presence of ICs, suggesting that ICs may play a role in developing pericarditis or that they may be considered a marker of pericarditis by an immunological mechanism.

Aged↗
PubMed1983

Stimulation of de novo methylation following limited proteolysis of mouse ascites DNA methylase.

The ability of mouse Krebs II ascites cell DNA methylase to add methyl groups to native, unmethylated DNA (de novo activity) is stimulated by limited proteolysis. The affinity of the enzyme for DNA is not altered by this treatment but the rate of reaction is increased so that 40% or more of methylatable sites are methylated within 4.5 h. The activation is associated with a decrease in size of the enzyme to 6.2 S.

Animals↗
PubMed1983

Reaction of beef plasma and lentil seedlings Cu-amine oxidases with phenylhydrazine.

The reaction of copper amine oxidases from beef plasma and lentil seedlings with hydrazine derivatives has been studied. A 1:1 stoichiometry was always found for the irreversible binding to the dimeric proteins. The formation of the adduct does not require the presence of oxygen or copper. Substrates compete with hydrazine derivatives for the binding to the enzymes. The binding of hydrazines and of substrate has different effects on the EPR spectra of enzymic copper.

Amine Oxidase (Copper-Containing)↗
PubMed1983

Essential sulfhydryl groups in diamine oxidase from Euphorbia characias latex.

Diamine oxidase from Euphorbia characias latex contains two sulfhydryl groups per mole of dimeric enzyme. The sulfhydryl groups are unreactive in the native enzyme but can be readily titrated by 4,4'-dithiodipyridine after protein denaturation, or anaerobically in the presence of the amine substrate. In the presence of both substrates (diamine and oxygen) they react sluggishly. The sulfhydryl groups show different reactivity toward various reagents, but in every case their modification inhibits catalytic activity. The insensitivity of the native enzyme to specific reagents suggests that the sulfhydryl groups are positioned in the interior of the protein and shielded from the solvent. Their reactivity in the presence of the amine substrate could be attributed to a conformational change occurring upon substrate binding or after substrate oxidation.

Amine Oxidase (Copper-Containing)↗
PubMed1983

Brief report: linkage between G6PD and fragile-X syndrome.

Eighteen Sardinian pedigrees segregating for the X-fragile site syndrome were studied with respect to the segregation of the fragile site (FS) at Xq28, mental retardation, and macro-orchidism. No exception was found in the association of this symptomatic triad (MOM-X) in 41 out of 42 patients examined. The exceptional individual had micro- rather than macro-orchidism and was found to have a 47, XXY sex chromosome complement. In six informative sibships, the MOM-X syndrome was found to segregate in close linkage association with G6PD-deficiency or protan colorblindness. The maximum likelihood estimate of recombination if 6% with 90% fiducial limits between 2.5 and 19.5% and an odds ratio in favor of measurable linkage of 428:1. However, no hint of measurable linkage was found in six pedigrees segregating for G6PD and the Renpenning syndrome or other unspecified types of X-linked mental retardation. These data give strong support to the generally held hypothesis that the FS at Zq28, characteristic of the MOM-X syndrome, is a direct expression of a genetic change in the same chromosomal region. They also clearly suggest that X-linked MR without FS may be the result of different allelic mutations at the same locus.

Color Vision Defects↗
PubMed1983

Glucose-6-phosphate dehydrogenase deficiency inhibits in vitro growth of Plasmodium falciparum.

Glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49)-deficient red blood cells from male hemizygotes and female heterozygotes from the island of Sardinia were studied for their ability to support growth in vitro of the malaria-causing organism Plasmodium falciparum. Parasite growth was approximately one-third of normal in both hemi- and heterozygotes for G6PD deficiency. In Sardinians with the beta 0-thalassemia trait, parasite growth was normal except when G6PD deficiency occurred together with the thalassemia trait. The data support the hypothesis that G6PD deficiency may confer a selective advantage in a malarious area; the female heterozygote may be at a particular advantage because resistance to malaria equals that of male hemizygotes, but the risk of fatal hemolysis may be less. However, more female heterozygotes must be studied to confirm this hypothesis. No protective effect of beta 0-thalassemia trait could be demonstrated in vitro.

Cells, Cultured↗
PubMed1983

The effect of X chromosome inactivation on the inhibition of Plasmodium falciparum malaria growth by glucose-6-phosphate-dehydrogenase-deficient red cells.

Previous data on in vitro culture of Plasmodium falciparum malaria demonstrated that red cell glucose-6-phosphate dehydrogenase deficiency (G6PD-) inhibited parasite growth in deficient hemizygous males. This study investigated the effect of heterozygosity for G6PD- on parasite growth. Blood was obtained from 8 female Sardinian G6PD- heterozygotes with G6PD normal cells ranging from 13% to 60%. For comparison, blood from a G6PD- hemizygous male, containing 100% deficient red cells, was mixed in different proportions with compatible normal blood. In both experiments, parasite growth was inhibited by the presence of deficient cells. In both cases, it was found that the inhibition could be explained by a simple dilution of normal cells by G6PD- cells. Thus, the typical female heterozygote is also protected to a significant extent. When considering the "malaria hypothesis" as it relates to G6PD, protection of the female heterozygote as well as the male hemizygote must be taken into account.

Erythrocytes↗
PubMed1982

Diamine oxidase from pig kidney: new purification method and amino acid composition.

Several methods for the isolation of apparently homogeneous pig kidney diamine oxidase have been reported in recent years (1-7), but these procedures allow to obtain only little amounts of material making very difficult the study of the molecular properties of the enzyme. Drawing useful indication from the purification procedures previously reported, we were able to set up a new method which allows to obtain homogeneous enzyme samples in high yield and with good reproducibility. This procedure allowed to determine with greater accuracy the molecular weight of the enzyme that resulted to be 170,000 daltons by gel chromatography and 145,000 by ultracentrifuge. The enzyme is composed of two apparently identical subunits and contains two copper atoms per dimer. The amino acid composition of the protein has been also worked out and found similar to those already reported for other copper dependent amine oxidases. Pig kidney diamine oxidase is a glycoprotein containing about 20% sugars by weight.

Amine Oxidase (Copper-Containing)↗
PubMed1982

Purification and properties of diamine oxidase from Euphorbia latex.

A diamine oxidase has been purified to homogeneity from the latex of an herbaceous shrub, Euphorbia characias. This enzyme has a relative molecular mass of 144,000 and is composed of two identical subunits. It contain two Cu(II) and two carbonyl-like groups per dimer. The purified enzyme is pink and shows a broad absorption in the visible region centered at 480 nm, which is modified by the addition of phenylhydrazine or semicarbazide. The electron paramagnetic resonance spectrum is typical of copper(II) in a tetragonal symmetry. This enzyme oxidizes putrescine and cadaverine at fairly high rate and, less efficiently a few related compounds, but not histamine, spermine or spermidine.

Amine Oxidase (Copper-Containing)↗