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Biomedical subjects

A Perin

Publications and source records attributed to A Perin.

At least 19 recordsLinked to original sources
PubMed1992

Diamine oxidase activity and related substrates in rat liver after chronic ethanol feeding.

Chronic ethanol feeding as 12% or 36% of total calories caused a dose-dependent diminution of diamine oxidase activity in rat liver. Hepatic cadaverine and histamine levels were unmodified by ethanol, whereas putrescine increased, partially in relation to the decrease in diamine oxidase activity. Such results may be of interest in view of an aggravation of ethanol-induced hepatic damage when exogenous diamines and polyamines reach the liver in potentially toxic amounts.

Alcoholism↗
PubMed1991

Spermidine N1-acetyltransferase activity in rat uterus after 17 beta-estradiol and during the estrous cycle.

The administration of 17 beta-estradiol to ovariectomized rats stimulated in uterus the activity of spermidine N1-acetyltransferase, the rate-limiting enzyme in the polyamine interconversion pathway. Such a stimulation was largely prevented by cycloheximide and actinomycin D, which indicates that it was due to an enzyme induction. During the estrous cycle, uterine enzyme activity was highest at proestrus and lowest at estrus, when estrogen plasma levels are known to be high and low, respectively. The induction of the enzyme was associated with the appearance or an increase in N1-acetylspermidine in uterus. The results suggest that estrogens regulate spermidine N1-acetyltransferase activity in uterus.

Acetyltransferases↗
PubMed1991

Increased synthesis of N1-acetylspermidine in hepatic preneoplastic nodules and hepatomas.

Hepatic preneoplastic nodules and hepatomas obtained in a multistep protocol of rat hepatocarcinogenesis (diethylnitrosamine, 2-acetylaminofluorene, and partial hepatectomy) showed high values of spermidine N1-acetyltransferase activity, the rate-limiting enzyme in polyamine interconversion. Such an increase was associated with the appearance of N1-acetylspermidine, an enhancement in putrescine, and a decline in spermine. Such changes suggest an activation of the interconversion pathway of high into lower polyamines in hepatic preneoplastic nodules and hepatomas.

2-Acetylaminofluorene↗
PubMed1991

Coenzyme A and hyperlipoproteinaemias.

Coenzyme A (CoA) exerts a favourable effect in lowering plasma lipids in patients with primary hyperlipoproteinaemias of phenotype IV (hypertriglyceridaemia) and of phenotype IIb (combined hyperlipidaemia). The mechanism by which CoA influences plasma lipids may be associated with the well-known role of this coenzyme in the catalysis of acylation reactions and in the control of lipid metabolism. The administration of CoA in animals fed on hyperlipidaemic diets reduces plasma lipid levels and causes a reduction of the hepatic concentrations of triglycerides and/or lipids. Mitochondria and peroxisomes isolated from liver of rats fed on a hyperlipidaemic diet and treated with CoA present an increased oxidation of palmitate. These results suggest that the primary effect of CoA is to increase fatty-acid oxidation in the liver that results in a decrease in endogenous synthesis of triglycerides as well as a reduced formation of VLDL and probably of cholesterol. The stimulation of fatty-acid oxidation in extrahepatic tissues may be also responsible for an increased catabolism of VLDL.

Clinical Trials as Topic↗
PubMed1990

Diamine oxidase activity in a model of multistep hepatocarcinogenesis.

Treatment of rats with a complete hepatocarcinogenic regimen (diethylnitrosamine, 2-acetylaminofluorene and partial hepatectomy) produced a prolonged stimulation of diamine oxidase activity in liver, which showed early and persistent preneoplastic nodules. Diethylnitrosamine or partial hepatectomy tested separately caused a transient increase in enzyme activity. Early nodules, which were positive for gamma-glutamyltransferase activity, and hepatomas showed diamine oxidase activity of approximately 5- and 13-fold that of control liver, respectively. These results indicate an activation of terminal catabolism of polyamines in preneoplastic nodules and in hepatomas.

2-Acetylaminofluorene↗
PubMed1990

Chronic ethanol feeding and diamine oxidase activity in rat brain and liver.

The activity of diamine oxidase, the principal enzyme for diamine catabolism, was evaluated in brain and liver from male rats fed nutritionally complete diets, of which 36% of total calories was given as ethanol or as isocaloric carbohydrates for 4 months. Ethanol caused an increase in diamine oxidase activity in the brain and a decrease in the liver, tissues with a low and high rate of ethanol oxidation, respectively.

Amine Oxidase (Copper-Containing)↗
PubMed1990

Estrogenic regulation of diamine oxidase activity in rat uterus.

Diamine oxidase activity was studied in female rat tissues during the estrous cycle and after 17 beta-estradiol administration. During the estrous cycle, uterine and hepatic enzyme activities were highest at proestrus and lowest at estrus, when estrogen plasma levels are known to be respectively high and low. The administration of 17 beta-estradiol to ovariectomized rats caused a rapid and prolonged increase in enzyme activity in uterus and only a transient increase in the liver. Such increases were prevented by cycloheximide and by actinomycin D administration. No changes were observed in renal enzyme activity during estrus or after hormone treatment. Our data suggest that estrogens regulate diamine oxidase activity in rat uterus by a mechanism of enzyme induction.

Amine Oxidase (Copper-Containing)↗
PubMed1990

Usefulness of the combined antithyroglobulin antibodies and thyroglobulin assay in the follow-up of patients with differentiated thyroid cancer.

A total of 1050 patients with differentiated thyroid cancer (DTC) have been followed in the Thyroid Center of Padua by means of serum thyroglobulin (Tg) measured with IRMA method and anti-Tg antibodies (TgAb) assays. Circulating TgAbs were detected in 102 (9.7%) patients. In 32 of these 102, TgAbs were evaluated before and after total thyroidectomy and 131I ablation. In these patients no relationship was found between preoperative serum TgAb levels on the one hand and tumor stage at diagnosis or outcome of the disease on the other. During the follow-up, TgAb serum levels decreased or disappeared in 21 cases considered tumor-free, while they remained unchanged or even increased, in comparison with the preoperative ones, in 11 patients, 5 with proven metastases and 6 considered tumor-free. Evaluating the whole group of 102 TgAb-positive patients, we observed that TgAb serum levels, measured after thyroid ablation, were significantly higher in cases with metastases than in those considered tumor-free (653.0 +/- 196.9 vs 157.7 +/- 116.5 U/ml, m +/- SD, p less than 0.0001). In the group of patients with metastases and circulating TgAbs, Tg serum levels were elevated in 27% of cases on TSH-suppressive therapy and in 44% off therapy when nodal metastases were present, and in 67% of cases on TSH-suppressive therapy and in 83% off therapy when distant metastases were present.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1989

Haematoporphyrin and atherosclerosis in the broad-breasted white turkey: distribution and quantitation in thoracic and abdominal aorta.

Rapidly replicating tissues such as malignant neoplasms accumulate porphyrins and often display a typical fluorescence. Previous authors observed a selective fluorescence due to injected porphyrins also in atheromatous plaques, while no fluorescence was observed in the plaque-free arterial wall. We have performed quantitative studies on the distribution of haematoporphyrin in the broad-breasted white turkey, in which hypertension and atherosclerosis occur spontaneously. In this experimental model the aortic atherosclerotic lesions are confined to the abdominal tract, and the thoracic tract exhibits a hypertrophic media. After haematoporphyrin injection, larger porphyrin concentrations were observed in the inner than in the outer portion of the abdominal aorta. An opposite behaviour was observed in the thoracic tract. Notably, haematoporphyrin was progressively cleared from the thoracic media, while its concentration remained relatively stable in the inner portion of the abdominal aorta up to four days after the injection. This indicates a selective and prolonged retention of haematoporphyrin within the atherosclerotic lesions.

Animals↗
PubMed1987

Polyamines and diamine oxidase activity in maternal, embryonal, and fetal tissues of rat after chronic ethanol consumption.

The effects of maternal ethanol consumption for 4 weeks before and throughout gestation on polyamine content and diamine oxidase activity of maternal, embryonal and fetal tissues are reported. At the 12th day of pregnancy, a decrease of putrescine in the liver of the mother and marked increases in putrescine, cadaverine and spermidine in embryos were observed. At day 18, putrescine and cadaverine diminished in maternal liver and placenta, and no changes in amine content in fetal liver and brain were found. At day 12, diamine oxidase activity increased in maternal liver and placenta, whereas it greatly diminished in embryos. At day 18, enzyme activity decreased in maternal liver, placenta, fetal liver and brain. These results indicate that chronic ethanol ingestion induces alterations in polyamine concentrations and metabolism in growing and developing tissues during pregnancy that might contribute to the adverse effect of ethanol on conceptual development.

Amine Oxidase (Copper-Containing)↗
PubMed1987

Effect of acute ethanol administration on diamine oxidase activity in maternal, embryonal and fetal tissues.

Pregnant rats were acutely treated with ethanol to study the influence of this drug on diamine oxidase activity of maternal, embryonal, and fetal tissues. When ethanol was given on day 12 of gestation, enzyme activity was unmodified in placenta and embryo, whereas it was reduced by 38 and 31%, respectively, in maternal liver and plasma at 3 h. When ethanol was given on day 18 of gestation, diamine oxidase activity diminished in maternal liver, plasma and placenta by about 35-40% at 6 h. Moreover, in the fetus ethanol caused a 35% diminution of enzyme activity in liver at 6 h and a 45% stimulation in brain at 3 h, and of about 65% at 6-12 h. These data may be of interest in view of the physiological role of diamine oxidase in the oxidation of the large amounts of amines produced during pregnancy.

Amine Oxidase (Copper-Containing)↗
PubMed1987

Ethanol and polyamine metabolism in adult and fetal tissues: possible implication in fetus damage.

The influence of ethanol treatment on various enzymes involved in the metabolism of polyamines, substances implicated in cell physiology, growth and differentiation, is reviewed. In particular, we studied the effect of acute in utero ethanol exposure on fetal liver diamine oxidase, the enzyme involved in the oxidative deamination of biogenic amines as well as in the terminal catabolism of polyamines. Ethanol, in contrast to that previously observed in adult rat liver, caused in fetal liver a significant diminution in diamine oxidase activity, which appeared reversible and was not dose-dependent with 2 or 4 g/kg body weight. These findings and the possible implication of altered polyamine metabolism in the pathogenesis of fetal alcohol syndrome are discussed.

Adult↗
PubMed1986

Response of tissue diamine oxidase activity to polyamine administration.

The administration to rats of putrescine (750 mumol/kg body wt.) caused in liver, kidney and heart an increase in putrescine at 1 h and in diamine oxidase (EC 1.4.3.6) activity within 3-6 h. An increase in spermidine was observed at 9 h in liver and at 6 h in kidney, whereas in heart there was no change. The increase in diamine oxidase activity by exogenous putrescine was prevented by the administration of actinomycin D and cycloheximide, suggesting that syntheses of mRNA and protein are involved. Equimolar doses of 1,3-diaminopropane, 1,5-diaminopentane and monoacetylputrescine stimulated, similarly to putrescine, hepatic, renal and cardiac diamine oxidase activity. After the injection of a non-toxic dose of spermidine (750 mumol/kg body wt.), the increase in diamine oxidase activity occurred at 9 h in all the tissues studied, when a substantial putrescine formation from spermidine occurred. sym-Norspermidine, which is unable to form putrescine, did not cause an increase in enzyme activity. The possibility that the tissue contents of putrescine might regulate diamine oxidase activity is discussed.

Amine Oxidase (Copper-Containing)↗
PubMed1986

Role of high-, low- and very low-density lipoproteins in the transport and tumor-delivery of hematoporphyrin in vivo.

Free hematoporphyrin administered intravenously to healthy rabbits (1-28 mg/kg body weight) is bound by the 3 major lipoprotein components of plasma (VLDL, LDL and HDL) with different efficiency. In vitro-prepared complexes of hematoporphyrin (Hp) with lipoprotein fractions isolated from mouse serum have been injected intracardiacally into mice affected by MS-2 fibrosarcoma (1 mg of Hp per kg body weight). LDL appear to allow a more specific delivery of the complexed Hp to the tumor tissue as compared with HDL, VLDL or free Hp. The different behavior of VLDL, LDL and HDL as carriers of Hp in vivo is also discussed.

Animals↗