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Biomedical subjects

F Petrelli

Publications and source records attributed to F Petrelli.

At least 19 recordsLinked to original sources
PubMed1990

Relationships between biotin and thymus morphology, and thymic and plasma peptides controlling DNA transcription.

Biotin-deficient rats show a slower growth rate and thymus involution. The amount of the thymic peptides controlling DNA template, based on thymus weight, is higher in deficient than control rats. No significant difference was noticed in the content of active peptides when evaluated for the rat. This observation suggests that involution of the thymus does not involve those cells which produce active peptides. Inhibition of RNA synthesis is the same for peptides extracted from normal and from biotin-deficient rat thymus. The amount of plasma peptides controlling DNA template per milliliter of plasma is higher and inhibition of activity on RNA synthesis is lower in deficient as compared to control rats. These effects are reversible following biotin administration.

Animals↗
PubMed1985

The effect of biotin on the formation of different types of E-rosettes by human lymphocytes.

Peripheral blood lymphocytes from healthy human donors were cultured with biotin and concanavalin A (Con A) for varying periods up to 48 h. At the end of incubation, the percentages of total, active, and stable E-rosettes were determined. The percentage of total E-rosettes decreased significantly in the course of time in both cultures with biotin and Con A, but more slowly than in the control cultures. Biotin and Con A induced a significant increase in the number of high-affinity E-rosettes (aE-RFC and sE-RFC). Preincubation for 4 h in the presence of puromycin or actinomycin D inhibited biotin, and Con A stimulated E-rosette formation. These results suggest that the effect of biotin on the T lymphocytes might be due to stimulation of protein synthesis and, perhaps, new receptors for sheep red blood cells (SRBC).

Biotin↗
PubMed1985

Relationships between biotin and DNA contents and DNA turnover in lymphoid organs: thymus, lymph nodes and spleen.

Biotin-deficient rats show a slower growth rate and a reduction in thymus, intestinal lymph nodes and spleen weight. The effect is reversible. Biotin administration to normal rats (1 mg/rat/day) causes an increase in intestinal lymph nodes and spleen, while there is no effect on body and thymus weight. The amount of thymus and spleen DNA is lower for deficient than control rats. No difference was noticed between the levels of DNA from normal control and biotin-deficient rat lymph nodes, and between the levels of DNA from normal rats treated and untreated with biotin. The time-course of the specific radioactivity of DNA and the DNA turnover shows that biotin increases both the incorporation of labelling in DNA and DNA turnover rate.

Animals↗
PubMed1984

Deaza analogues of adenosine as inhibitors of blood platelet aggregation.

A number of deaza analogues of adenosine were prepared and tested as inhibitors of platelet aggregation induced by ADP and collagen to investigate the structure-activity relationships in this class of nucleoside analogues. The results showed that the presence of a 6-amino group and nitrogen atoms at positions 3 and 7 of the purine moiety are required for inhibitory activity.

Adenosine↗
PubMed1980

Behaviour in biotin-deficient rats of thymic peptides controlling DNA transcription.

Biotin-deficient rats show a slowing down of the growth and an involution of the thymus. The amount of the thymic peptides controlling DNA template, if referred to the thymus weight is higher in deficient than in control rats; no significant difference is noticed among the contents of the active peptides when evaluated per rat. The inhibiting activity on RNA synthesis is the same for the peptides extracted from normal and from biotin-deficient rat thymus.

Animals↗
PubMed1979

Intracellular distribution of biotin-14COOH in rat liver.

Biotin clearance, its distribution in liver and liver fractions after intravenous administration of 5 muCi/100 g body weight (21.55 microgram) of biotin-14COOH in normal and biotin-deficient rats are reported. In the biotin deficient animal there is a more rapid disappearance of the labeled biotin from the blood stream. Biotin-14COOH incorporation in the liver of the deficient rat is more rapid and larger than the incorporation in normal rat liver. Almost all the biotin recovered from liver homogenate is found in the mitochondria and in the pH 5.2 cytosol fraction; whereas in the microsomes only a very small amount is present. The intracellular distribution of biotin is in agreement with its known metabolic roles.

Animals↗
PubMed1978

Effects of biotin deficiency on serum proteins and plasma amino acids.

In biotin-deficient rats, a decrease of total proteins, attributable to a decrease of albumin and alpha1-globulin fractions, a decrease of the pre-beta-lipoproteins and an increase of the alpha-lipoproteins, was observed, together with a rise of total amino acids. Such a situation may be related to the influence of biotin on the synthesis of RNA and proteins.

Alpha-Globulins↗
PubMed1978

Effect of biotin on phosphorylation, acetylation, methylation of rat liver histones.

Biotin deficient rat liver histones showed decreased phosphorylation and methylation, and increased acetylation rates as compared to normal rat liver histones: these alterations may be related to the observed lower stability of the interactions between histones and DNA. The modifications of the metabolic process might be the consequence of an alteration of the synthesis of the enzymes involved in histone phosphorylation, acetylation and methylation mechanisms and are presumably related to a biotin effect upon the synthesis of RNA and proteins.

Acetates↗
PubMed1977

Effect of biotin on DNA and histone phosphorylation in the rat liver.

The results offer further evidence for biotin activity in the phosphorylation mechanism. The decreased 32p incorporation into DNA and histones found in the biotin deficient rat liver is indicative of the importance of the vitamin in the DNA and histones synthesis and in the interactions between histone proteins and DNA, and consequently on the RNA and proteins synthesis.

Animals↗
PubMed1976

Platelet aggregation inhibitors. II - N-heterocyclic aldoxime methiodides (1).

On the basis of an hypothesis according to which suitable nucleophilic agents may convert adenosine diphosphate (ADP) into adenosine monophosphate (AMP) and adenosine, well known inhibitors of ADP-induced platelet aggregation, some N-heterocyclic aldoxime methiodides were tested as inhibitors of ADP-induced rabbit platelet aggregation. Several 1-aryl-2-hydroxyiminomethly-3-methylimidazolium iodides significantly inhibit in vitro and in vivo-in vitro ADP-induced rabbit platelet aggregation.

Adenosine Diphosphate↗
PubMed1975

[Derivatives of imidazo[1,2-c]quinazoline with inhibiting effect on platelet aggregation].

Several 5-monosubstituted and 5,5-disubstituted 5,6-dihydroimidazo[1,2-c]quinazolines were synthesized in high yields by the condensation of 2-(o-aminophenyl)imidazole with the required aliphatic or aromatic aldehydes or ketones. Some of these compounds caused inhibition of ADP-induced platelet aggregation in vitro at concentration of 10(-5) to 10(-4) M. The structure-activity relationships of these inhibitors are discussed.

Animals↗