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Biomedical subjects

E Marinello

Publications and source records attributed to E Marinello.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Purine bases and atheromatous plaque.

In this work we determined hypoxanthine (HX), xanthine (X), uric acid (UA), allantoin (ALL) and free radicals in atheromatous plaques to improve the comprehension of oxidative stress, a phenomenon which characterizes the evolution of atherosclerotic lesions. Carotid artery plaque were obtained from subjects undergoing endoarterectomy. Pulverized plaque, extracted by water, was used for analysis of oxidative stress factors (allantoin, uric acid, xanthine, hypoxanthine, free radicals). The peroxidation UA-->ALL was very high in the plaque, as was the level of free radicals. The results show that oxidative degradation of nucleotides, such as LDL oxidation, plays a specific role not only in the progression of atherosclerotic lesions but also in the advanced plaque.

Allantoin↗
PubMedDate not supplied

Activation and inhibition of rat liver L-threonine dehydrogenase.

We have studied some characteristics of mitochondrial rat liver L-threonine dehydrogenase during freezing: the enzyme shows a net increase in activity and a "shift" in the pH optimum after storage at -20 degrees C of mitochondrial preparations. An unknown effector, which inhibited significantly the dehydrogenase activity, was isolated from the same preparations kept for 7-10 days at -20 degrees C. Some properties of the inhibitor have been determined.

Alcohol Oxidoreductases↗
PubMedDate not supplied

The hormonal regulation of purine nucleotide turnover. Influence of testosterone in rat liver.

An influence of testosterone on de novo purine nucleotide synthesis has been demonstrated in rat liver of adult and prepubertal castrated rats, showing that the action of the hormone is not limited to sexual organs. Castration accelerated the turnover of purine nucleotides in adults rats and reduced it in prepubertal castrated rats. Administration of testosterone tended to restore normality in both cases with opposite mechanisms, lowering the reaction rates in the first group, enhancing them in the second one. An action of the hormone on the inosinic branch-point and specifically on GMP synthesis, was evident, which was again different according to the age of the animal. The observed changes in purine nucleotide metabolism could be responsible for variations in RNA and DNA metabolism, in cellular size and number--which probably occur in the liver--after orchiectomy and following androgen administration.

Adenine↗
PubMedDate not supplied

Primary structure of rat liver L-threonine deaminase.

The primary structure of rat liver L-threonine deaminase has been studied utilizing a highly purified preparation (S.A. = 940 U/mg protein) obtained from Wistar male rats. These data have been compared with the predicted sequences obtained by other Authors, showing a considerable concordance with the Noda's prediction and difference with the Ogawa's results. The FAB-MS analysis has demonstrated the presence of an acetyl group as blocking agent on the N-terminal alanine.

Amino Acid Sequence↗
PubMedDate not supplied

Amino acid sequence around the pyridoxal 5'-phosphate binding site of rat liver L-threonine deaminase.

Rat liver L-threonine deaminase is a pyridoxal 5'-phosphate dependent enzyme. In the present study we have studied the amino acid sequence composition of the peptide surrounding the coenzyme binding lysine at the active site of the native enzyme. We have also examined the homology between this peptide and the analogue forms of L-threonine deaminase from different sources.

Amino Acid Sequence↗
PubMedDate not supplied

Effect of testosterone on RNA and DNA synthesis in rat perineal muscle.

Nucleid acid metabolism in the LAM of the rat, both before and after castration, and during testosterone treatment, was investigated. RNA synthesis was increased by testosterone treatment, to varying degree, in adult and in prepubertal castrated rats, and was not merely dependent on the degree of hypertrophy of the LAM. The DNA content and the incorporation rate of formate-14C into DNA showed a characteristic profile under the same conditions: the atrophy of LAM following castration and its subsequent restoration appeared to be accompanied by variations in nuclei number. The possible role of testosterone in DNA duplication and in cell mitosis is hypothesized here; further investigation must be integrated by careful morphometric observation.

Aging↗
PubMedDate not supplied

Catabolism of purine ribonucleotides and glucocorticoid hormones in the rat.

We have studied, in vivo, the catabolism of purine nucleotides (inosinic, guanylic and adenylic acid) in the rat and its regulation by the glucocorticoid hormones, following the behavior of liver xanthine oxidase and the incorporation of formate-14C into urinary allantoin. An original method for purification of urinary allantoin has been developed. A slight acceleration of purine catabolism in adrenalectomized rats--both treated and untreated with corticosterone--was observed, while the normal behavior was restored during cortisone and cortisol treatment. The liver xanthine oxidase activity is unchanged in the different conditions. We conclude that the glucocorticoid hormones have only a slight, not relevant and probably not specific effect on purine catabolism in the whole body.

Adrenalectomy↗
PubMedDate not supplied

The regulation of purine ribonucleotide biosynthesis by glucocorticoid hormones.

The influence of the glucocorticoid hormones (cortisone, cortisol, corticosterone) on the biosynthesis of purine nucleotides (inosinic acid, guanylic acid and adenylic acid) in different organs was investigated in vivo, by following the incorporation of formate-14C into the acid-soluble nucleotides, after administration of the hormones to adrenalectomized rats. Cortisone and corticosterone show a remarkable and comparable increase of the incorporation of formate-14C only in the purine bases of the liver: cortisol is much more effective, increasing the incorporation of formate-14C into the purine bases even ten times over the basal values. No specific effect is evident either in the kidney or in the heart after glucocorticoid administration. Results are interpreted considering that the action of an individual hormone is specifically restricted to the purine nucleotide synthesis in the liver, and that cortisol seems to be the most efficient from this point of view.

Adrenalectomy↗