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Biomedical subjects

M E Ferioli

Publications and source records attributed to M E Ferioli.

At least 19 recordsLinked to original sources

Aging and polyamine acetylation in rat kidney.

The acetylation of polyamines was investigated in rat kidney as a function of age. The activity of cytosolic spermidine/spermine N1-acetyltransferase, the rate-limiting enzyme in polyamine interconversion, increased from 3 to 36 months of age. The activity of cytosolic spermidine N8-acetyltransferase, an enzyme probably related to polyamine excretion, also increased. The activity of polyamine oxidase, which catalyzes the oxidative cleavage of polyamine N1-acetyl derivatives into putrescine, decreased until 24 months, when an accumulation of N1-acetylspermidine occurred. Subsequently, at 36 months, polyamine oxidase activity returned toward high values, in concomitance with the disappearance of N1-acetylspermidine, an increase in spermidine and putrescine, and a decline in spermine was observed. Our results show that in rat kidney during aging there is an activation of the acetylation and interconversion of higher polyamines into putrescine, which is considered an alternative pathway of spermidine and putrescine formation.

Acetylation

Persistent decrease in spermidine/spermine N1-acetyltransferase activity in 'post-regeneration' rat liver.

The activity of cytosolic spermidine/spermine N1-acetyltransferase and polyamine levels were measured in livers of rats killed at different times after partial hepatectomy. The enzyme activity, which showed an early increase a few hours after the operation, had significantly and persistently decreased by the time the liver mass had been regained (10 days) compared to intact rats or sham-operated rats, and up to 30 days after partial hepatectomy, compared to intact rats of the same age. The early induction of spermidine/spermine N1-acetyltransferase activity was also confirmed by the high level of N1-acetylspermidine, which normally is undetectable, and by a dramatic increase in putrescine content. Spermidine levels were increased during the first 10 days after partial hepatectomy, i.e., when the liver had regained its mass, and progressively decreased after this time until 30 days after the operation. The changes in spermine content were similar but not as marked as the changes in spermidine content at the different observation times.

Acetyltransferases

Subacute combined degeneration and induction of ornithine decarboxylase in spinal cords of totally gastrectomized rats.

Totally gastrectomized rats have been used to induce a spongy demyelination in the white matter of the spinal cord (SC) which is strongly reminiscent of that observed in subacute combined degeneration of human SC. Totally gastrectomized rats are deprived of intrinsic factor and thereafter become deficient in cobalamin. Morphologically, the spongy demyelination of the white matter of the rat SC, was evident 2 months after total gastrectomy. Biochemically, we investigated the hypothesis that polyamine biosynthesis might be deranged in the rat SC with experimental subacute combined degeneration, since polyamines are well known to be bound to myelin in the mammalian central nervous system. We measured the levels of both the polyamine biosynthetic decarboxylases, L-ornithine decarboxylase (ODC) and S-adenosyl-L-methionine decarboxylase, the key points in the polyamine biosynthetic pathway, in these SC. There was a sharp increase in ODC activity in SC 2 months after total gastrectomy, without significant changes in S-adenosyl-L-methionine decarboxylase activity. The increase in ODC activity seems to be organ-specific and was not due to a proliferation of neuroglial cells. Interestingly enough, the same morphologic and biochemical features found in SC of 2-month-totally-gastrectomized rats were present also in SC of newborn rats, which indeed showed incomplete myelination, vacuolated appearance, and an ODC activity level higher than that of adult SC. Therefore, total gastrectomy seems to induce a type of regression in the SC of totally gastrectomized rats toward neonatal life, at least in terms of the degree of myelination and of ODC activity level. Biochemically, no changes in ODC activity were observed in SC of rats fed a cobalamin-deficient diet for 3 months. Morphologically, only a proliferation of neuroglial cells with a moderate demyelination was observed in SC of these rats maintained on a cobalamin-deficient diet for 3 months.

Animals

Polyamine biosynthetic decarboxylases in muscles of rats with different experimental myopathies.

The activities of the two polyamine biosynthetic decarboxylases (PBD), L-ornithine decarboxylase (ODC) and S-adenosyl-L-methionine decarboxylase (SAMD), have been measured in quadriceps femoris of rats killed at different times after the induction of calciphylaxis- or serotonin(5-HT)-induced myopathy. Decreases in both PBD levels were observed at early times after both myotoxic treatments. Subsequent progressive increases in both enzyme levels were observed to nearly control values by 4 days after 5-HT administration. In the 5-HT-treated rats, the effects on the myocardial PBD activities were different from those in skeletal muscle, with no effect on ODC but much on SAMD, when rats were killed shortly after 5-HT injection. These results demonstrate that the time-course of the changes in PBD activities in quadriceps femoris mirrors quite well the successive occurrence of degenerative and regenerative processes during the calciphylaxis-induced myopathy and the 5-HT-induced myopathy; it is 5-HT that is mainly responsible for the decreases in PBD levels observed in both experimental myopathies, since dihydrotachysterol alone was without any effect on PBD activity levels and 5-HT alone was effective; myocardial ODC reacts more slowly to 5-HT than quadriceps femoris ODC.

Adenosylmethionine Decarboxylase

Activation of polyamine biosynthetic decarboxylases during the acute phase response of rat liver.

The activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase increase in the livers of rats during the acute-phase response to inflammation. The increase reaches its maximum at 2.5 hr from injection of turpentine, and is maintained at the same level for the following 2 days. Pretreatment in vivo with an inhibitor of cyclooxygenase prevents the inflammation-associated increases of both polyamine biosynthetic decarboxylases: an inhibitor of the lipoxygenase pathway seems to counteract only the increase of ornithine decarboxylase. The administration of diaminopropane, an inhibitor of ornithine decarboxylase, has only limited effects on the activation of RNA synthesis by liver nuclei, which occurs 10 hr after turpentine treatment. The results suggest that stimulation of the polyamine biosynthetic decarboxylases is surely part of the acute-phase response and depends on the previous activation of arachidonate metabolism: however its role in supporting later events of the acute-phase response will need further investigations.

Acute-Phase Reaction

Prostaglandin synthesis and early biochemical events in the liver cells during the acute-phase response.

Acetylsalicic acid and indomethacin suppress the increase of alpha-amanitin sensitive RNA synthesis (pre-mRNA), but not that of alpha-amanitin resistant RNA synthesis (pre-rRNA), which occur in liver nuclei a few hours after the start of turpentine-induced inflammation in the skin. The inflammation-associated increase in activity of nuclear ATP-ase is also prevented. Synthesis of prostaglandins PGE2 and PGE2 alpha by liver microsomes from turpentine-treated rats is enhanced within 90 min. from treatment. The results suggest an important role of intracellular prostaglandins as mediators of the early nuclear events occurring in the liver at the beginning of the acute-phase response to inflammation.

Acute-Phase Reaction

Persistently decreased hepatic levels of 5'-deoxy-5'-methylthioadenosine during regeneration of and chemical carcinogenesis in rat liver.

The hepatic levels of 5'-deoxy-5'-methylthioadenosine (MTA) were measured in the livers of adult male Sprague-Dawley rats a) killed at various times during the liver regeneration process, b) killed at times after partial hepatectomy when the liver mass had already been completely restored (hereafter called post-regeneration livers), or c) continuously fed 3'-methyl-4-dimethyl-aminoazobenzene (CAS: 55-80-1) up to the full development of hepatoma and killed at regular intervals during hepatocarcinogenesis. Hepatic MTA levels were always significantly decreased, although to different degrees in both in vivo models of hepatic growth and at all times during the investigation. Astonishingly, the MTA levels were also significantly decreased in the post-regeneration livers, in which there was also a significant increase in the activity of adenosylmethionine decarboxylase (S-adenosyl-L-methionine decarboxylase; EC 4.1.1.50) with normal levels of activity of ornithine decarboxylase (EC 4.1.1.17). These results demonstrate that a) the MTA content is always decreased in rat liver whenever this organ is involved in a proliferative process (whether controlled or uncontrolled); b) the decrease in hepatic MTA content is a biochemical feature necessary for, but by no means by itself sufficient for, hepatocyte proliferation to occur, since this decrease remains long after complete restoration of the liver mass; and c) the return of the hepatocytes to the normal biochemical program after restoration of the liver mass is not complete, even though these cells become quiescent, because there are still some biochemical abnormalities in the post-regeneration livers.

Animals

Degree of enhancement of polyamine biosynthetic decarboxylase activities in human tumors: a useful new index of degree of malignancy.

We have determined the levels of L-ornithine decarboxylase (ODC) and S-adenosyl-L-methionine decarboxylase (AMD) in 134 untreated human primary tumors, such as skin epitheliomas and brain tumors. The levels of both decarboxylases increase in proportion to the grade of malignancy (ascertained by histologic criteria) in both the basal cell and squamous cell carcinomas of the skin. In the various types of brain tumors, ODC levels are more reliable indications of the grade of malignancy than AMD levels. In fact, the highest ODC levels observed in medulloblastoma and in astrocytoma grade IV were not associated with similarly high AMD levels. The same dichotomy between the levels of the two decarboxylases was observed for meningiomas, in which ODC levels were higher in atypical forms (with karyokinesis) then in typical forms (without karyokinesis).

Adenosylmethionine Decarboxylase

Polyamines in mammalian ageing: an oncological problem, too? A review.

This review surveys the literature about changes in polyamine contents and levels of activity of the enzymes involved in the polyamine biosynthetic pathway in organs of ageing mammals. The literature about changes in the polyamine levels in physiological fluids in healthy ageing humans is also reviewed. Generally speaking, decreases in the levels of the main polyamines (noticeably putrescine and spermidine) are observed in different mammalian organs with ageing. The polyamine levels in serum and in urine of healthy human beings are also age-related, declining progressively with increasing age. Some major enzymes (i.e., ornithine decarboxylase (EC 4.1.1.17) and S-adenosyl-L-methionine decarboxylase (EC 4.1.1.50) involved in the polyamine biosynthetic pathway show similar trends. Hormonal induction of ornithine decarboxylase activity is strongly reduced in organs of aged animals, as it is in neoplastic organs. There is also some evidence for an age-related decrease in the level of ornithine decarboxylase and its inducibility in mammalian cells cultured in vitro. Some in vitro effects of spermidine and spermine on aged structures or systems are briefly summarized. There is no evidence yet that this generally reduced capacity of mammalian aged organs for polyamine biosynthesis is one of the factors responsible for the well known high incidence of some neoplasias in elderly humans. In view of the typical stimulatory effects of the tumour promoters on polyamine biosynthesis in target tissues and the effects of senescence on the same metabolic pathway, it can be excluded that the ageing process has a tumour promoting effect by itself. However, although the exact mechanism responsible for the increased occurrence of some tumors during mammalian senescence is still obscure, there are enough experimental data (both in humans and in animals) to indicate that the reduced polyamine biosynthetic capacity of aged mammals can account for the slower course of some tumors in elderly patients.

Adenosylmethionine Decarboxylase

Permanent decrease in activity of ornithine decarboxylase antizyme in rat liver during chemical hepatocarcinogenesis.

This study was undertaken to determine whether or not there is failure of cellular control of L-ornithine decarboxylase activity by its antizyme, the only known natural intracellular inhibitor protein for L-ornithine decarboxylase activity, in rat liver during hepatocarcinogenesis induced by 3'-methyl-4-dimethylaminoazobenzene. The formation of hepatic ornithine decarboxylase antizyme was elicited by i.p. injections of putrescine into rats fed a basal diet and rats fed the carcinogenic diet. The activities of both hepatic ornithine decarboxylase and hepatic ornithine decarboxylase antizyme were measured every month for five months, i.e., until hepatoma was fully developed. During azo-dye hepatocarcinogenesis and in fully developed hepatoma the activity of hepatic ornithine decarboxylase antizyme was always significantly lower than in normal resting liver, with minima at the second and the third months. The hepatoma does not synthesize ornithine decarboxylase antizyme more slowly than normal liver, since the difference could be neither abolished nor lessened by lengthening the time available for antizyme formation. Our results strongly suggest that the high intracellular putrescine levels in the livers of rats during 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis do not exert their normal control on hepatic ornithine decarboxylase activity because of a relative inability of these preneoplastic or neoplastic cells to make the ornithine decarboxylase antizyme.

Animals

Restoration of normal ornithine decarboxylase antizyme activity in rat liver after acute carcinogen treatment.

This study was undertaken to see whether or not the decrease in ornithine decarboxylase antizyme activity caused in rat liver by a hepatocarcinogen could be reversed. Thioacetamide was administered only once, in a single i.p. injection and at a non-carcinogenic, non-necrogenic dose. The activities of both hepatic ornithine decarboxylase and hepatic ornithine decarboxylase antizyme were measured at intervals of hours after the injection of thioacetamide. The hepatic ornithine decarboxylase antizyme in thioacetamide-treated rats was minimal at 40 and 80 h after carcinogen administration. The reversal process requires a very long time, namely 450 h for normal levels of hepatic ornithine decarboxylase antizyme activity to be restored in treated rats. This time is much longer than that required to restore normal ornithine decarboxylase activity in liver of thioacetamide-treated rats. The results of this study, combined with those of the preceding paper, demonstrate that hepatocarcinogens cause a relative inability of rat liver cells to make the ornithine decarboxylase antizyme and that the irreversibility of this defect in cellular control of ornithine decarboxylase activity may be a constant feature in the neoplastic transformation of the rat liver.

Acetamides

Degrees of malignancy in human primary central nervous system tumors: ornithine decarboxylase levels as better indicators than adenosylmethionine decarboxylase levels.

The levels of activity to ornithine decarboxylase (ODC) and adenosylmethionine decarboxylase (AMD) were measured in various types of primary human tumors of the central nervous system (CNS) and whenever possible were related to the malignancy of the tumor graded according to histopathologic criteria. In astrocytomas ODC levels increased linearly and progressively from infratentorial pilocytic astrocytoma (grade I) to glioblastoma multiforme (grade IV) and corrected well with the degree of histologic malignancy of the tumor. AMD activity levels, however, correlated with tumor malignancy only up to grade III astrocytoma. Medulloblastomas exhibited an unusual dichotomy with regard to the levels of polyamine biosynthetic decarboxylases (PBD): Medulloblastomas had the highest ODC activities of all the CNS tumors tested but had low AMD activities. In tumors of neuroepithelial tissue ODC level increases and, when present, AMD level increases were not due to proliferation of new blood vessels, because CNS hemangioblastomas had very low levels of both PBD activities. No significant differences in either of the PBD levels were observed among the several variants of meningiomas tested, the meningotheliomatous, the transitional, and the fibrous meningiomas. However, atypical forms of meningioma, i.e., those with mitotic figures, whatever the histologic variants, had higher levels of ODC, but not of AMD, than the typical forms, i.e., those without mitotic figures.

Adenosylmethionine Decarboxylase