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1.
Clin Oncol (R Coll Radiol) ; 35(10): 682-693, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37558548

RESUMO

AIMS: To report toxicity profile, outcomes and quality of life (QoL) data in patients with recurrent gynaecological cancer who underwent stereotactic body radiotherapy (SBRT) retreatment. MATERIALS AND METHODS: Data from patients' folders were retrospectively extracted, focusing on the primary neoplasm, previous systemic therapies and previous radiotherapy. Concerning SBRT, the total dose (five daily fractions) was delivered with a linear accelerator using intensity-modulated radiotherapy techniques. Acute and late toxicities were assessed by the CTCAE 4.03 scale. QoL was evaluated according to the Cancer Linear Analogue Scale [CLAS1 (fatigue), CLAS2 (energy level), CLAS3 (daily activities)]. RESULTS: Between December 2005 and August 2021, 23 patients (median age 71 years, range 48-80) with 27 lesions were treated. Most patients had endometrial (34.8%), ovarian (26.1%) and cervical cancer (26.1%) as the primary tumour. The most common SBRT schedules in five fractions were 30 Gy (33.3%), 35 Gy (29.6%) and 40 Gy (29.6%). The median follow-up was 32 months (range 3-128). There were no patients reporting acute or late toxicities higher than grade 2, except for a bone fracture. One- and 2-year local control was 77.9% and 70.8%, respectively. One- and 2-year overall survival was 82.6% and 75.1%, respectively. The overall response rate was 96.0%. Regarding QoL, no statistically significant difference was identified between the baseline and follow-up values: the median CLAS1, CLAS2 and CLAS3 scores for each category were 6 (range 4-10) at baseline and 6 (range 3-10) 1 month after SBRT. CONCLUSIONS: This preliminary experience suggests that SBRT retreatment for recurrent gynaecological cancer is a highly feasible and safe treatment with limited side-effects and no short-term QoL impairment.


Assuntos
Neoplasias , Radiocirurgia , Reirradiação , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Qualidade de Vida , Reirradiação/efeitos adversos , Reirradiação/métodos , Estudos Retrospectivos , Radiocirurgia/efeitos adversos , Radiocirurgia/métodos , Recidiva Local de Neoplasia/cirurgia
2.
Chest ; 163(4): e163-e166, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37031987

RESUMO

CASE PRESENTATION: A 60-year-old man was referred to a pulmonologist evaluation with persistent dyspnea and cough 1 month after discharge for an acute respiratory failure caused by Legionella pneumophila pneumonia, which required invasive mechanical ventilation. Chest CT scan performed during hospitalization showed lobar consolidation of upper left lobe (Fig 1A). Bronchial culture revealed L pneumophila; the patient was treated with levofloxacin and supported with invasive mechanical ventilation for 2 weeks. Chest radiograph after extubation showed almost complete resolution of infiltrates. After 1 month, the patient still complained of dyspnea and a new chest CT scan was performed: the consolidation migrated (Fig 1B; Video 1).


Assuntos
Legionella pneumophila , Doença dos Legionários , Ventilação não Invasiva , Masculino , Humanos , Pessoa de Meia-Idade , Pulmão , Dispneia
3.
J Food Prot ; 80(3): 443-446, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28207305

RESUMO

Ice cream, a popular product worldwide, is usually a milk-based product with other types of ingredients (fruit, eggs, cocoa, dried fruit, additives, and others). Different materials are used to obtain the desired taste, texture, consistency, and appearance of the final product. This study surveyed ice cream products available in Italy for heavy metals (lead, cadmium, chromium, tin, and arsenic). The differences between artisanal and industrial ice cream were also investigated because of the importance in the Italian diet and the diffusion of this ready-to-eat food. Ice cream sampling was performed between October 2010 and February 2011 in the northeast of Italy. A total of 100 samples were randomly collected from different sources: 50 industrial samples produced by 19 different brands were collected in coffee bars and supermarkets; 50 artisanal ice cream samples were gathered at nine different artisanal ice cream shops. Ten wooden sticks of industrial ice cream were analyzed in parallel to the ice cream. All samples were negative for arsenic and mercury. None of the artisanal ice cream samples were positive for lead and tin; 18% of the industrial ice cream samples were positive. All positive lead samples were higher than the legal limit stated for milk (0.02 mg/kg). All industrial ice cream samples were negative for cadmium, but cadmium was present in 10% of the artisanal ice cream samples. Chromium was found in 26% of the artisanal and in 58% of the industrial ice cream samples. The heavy metals found in the wooden sticks were different from the corresponding ice cream, pointing out the lack of cross-contamination between the products. Considering the results and the amount of ice cream consumed during the year, contamination through ice cream is a low risk for the Italian population, even though there is need for further analysis.


Assuntos
Contaminação de Alimentos , Sorvetes , Animais , Arsênio , Itália , Metais Pesados
4.
Cell Mol Life Sci ; 61(21): 2767-73, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15549180

RESUMO

The suggestion has been made that polyamines may be involved in the control of cell death, since exceedingly high or low levels induce apoptosis in different cell systems. For a deeper insight into the relationship between apoptosis and polyamine metabolism, we investigated in vitro the effect on rat thymocytes of mitoguazone (MGBG, which inhibits S-adenosylmethionine decarboxylase, i.e. a key enzyme in the polyamine biosynthetic pathway). Thymocytes were selected as an especially suitable model system, since they undergo spontaneous apoptosis in vivo and can be easily induced to apoptose in vitro by etoposide, used here as an apoptogenic agent. MGBG protected thymocytes from both spontaneous and drug-induced apoptosis, and this protective effect was associated with a decrease in polyamine oxidase activity and total polyamine levels.


Assuntos
Apoptose/efeitos dos fármacos , Etoposídeo/farmacologia , Mitoguazona/farmacologia , Timo/citologia , Timo/efeitos dos fármacos , Animais , Anexina A5/metabolismo , DNA/análise , DNA/metabolismo , Mitoguazona/administração & dosagem , Ratos , Timo/metabolismo
6.
Amino Acids ; 24(1-2): 187-94, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12624752

RESUMO

To extend the knowledge on the role of polyamine oxidase in thymus physiology, we evaluated the in vivo effect of the polyamine biosynthetic pathway inhibitor mitoguazone. The drug markedly and permanently decreased the enzyme activity in the organ, in which the level of putrescine also decreased at the later times observed. A byproduct of the reaction catalyzed by polyamine oxidase is hydrogen peroxide, a well known inducer of apoptosis. The decrease in polyamine oxidase activity, with the consequent decrease in hydrogen peroxide production, is correlated with a positive effect on thymus physiology. Since mitoguazone has been successfully employed in patients with AIDS-related diseases, in which the reconstitution of the immune function is a favorable prognostic index, we hypothesized that mitoguazone may have the thymus as target organ, and that the decrease in polyamine oxidase activity may have a role in the positive effect of the drug.


Assuntos
Inibidores Enzimáticos/farmacologia , Mitoguazona/farmacologia , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Timo/enzimologia , Animais , Citometria de Fluxo , Masculino , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Ratos , Ratos Wistar , Poliamina Oxidase
7.
Mol Cell Endocrinol ; 165(1-2): 51-6, 2000 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-10940483

RESUMO

Much evidence suggests that prolactin has an immunoregulatory function and that its effects on cells of the immune system depend on the level and specific forms of the receptors present on the target cells. The effect of administration of prolactin on polyamine catabolism was investigated in thymus of male intact rats by measuring the activities of spermidine/spermine N(1)-acetyltransferase and polyamine oxidase, because of the relationships between polyamines (especially putrescine) and the immune system. The administration of prolactin to rats resulted in the rapid induction of spermidine/spermine N(1)-acetyltransferase activity in the thymus (1.6-times the level of control rats, within 4 h), and in a marked decrease in polyamine oxidase activity at 24 h. The changes in enzyme activities were accompanied by an increase in putrescine concentration and a decrease in spermidine and spermine concentrations. In the spleen, prolactin increased SAT activity only 24 h after administration and was ineffective on PAO activity.


Assuntos
Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Poliaminas/metabolismo , Prolactina/farmacologia , Timo/efeitos dos fármacos , Timo/metabolismo , Acetiltransferases/metabolismo , Animais , Masculino , Putrescina/metabolismo , Ratos , Ratos Wistar , Espermidina/metabolismo , Espermina/metabolismo , Baço/efeitos dos fármacos , Baço/enzimologia , Baço/metabolismo , Timo/enzimologia , Poliamina Oxidase
8.
Biochem Pharmacol ; 58(12): 1907-14, 1999 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-10591145

RESUMO

Glucocorticoids are known to negatively affect lymphoid tissues, in which they cause programmed cell death. Polyamine depletion, which occurs in glucocorticoid-treated animals by inhibition of biosynthesis and induction of acetylation, may represent a signal to thymocytes for progression into the apoptotic program. Since catalysis of polyamines by the catabolic pathway produces hydrogen peroxide as a by-product, it has been suggested that the apoptotic process may be, in part, due to oxidative stress as a result of hydrogen peroxide production. In order to verify whether polyamine oxidase (EC 1.5.3.11) may play a role in the process, we examined the activity of the enzyme in the thymus and spleen of glucocorticoid-treated rats. We administered dexamethasone (4 mg/kg) or two different doses of corticosterone (4 mg/kg or 30 mg/kg) to rats, which were killed 8 or 24 hr after hormone injection. We found that corticosterone and dexamethasone affected polyamine oxidase activity in both tissues, with an opposite dose-dependent effect of the natural hormone in the thymus. The decrease and increase in polyamine oxidase after the two doses of corticosterone were correlated with the absence and the occurrence of DNA fragmentation, respectively. Moreover, corticosterone affected polyamine oxidase activity earlier (8 hr) than dexamethasone (24 hr), but the synthetic hormone was more efficient than the natural hormone in thymic polyamine depletion. The polyamine oxidase response may represent an important event in lymphoid tissues after glucocorticoid treatment, suggesting a role of the enzyme in the catabolic effects exerted by the two hormones.


Assuntos
Tecido Linfoide/enzimologia , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Corticosterona/farmacologia , Tecido Linfoide/efeitos dos fármacos , Masculino , Poliaminas/metabolismo , Ratos , Ratos Wistar , Poliamina Oxidase
9.
Amino Acids ; 17(2): 139-48, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10524272

RESUMO

Variations in level of polyamines and their related enzymes are frequently observed in response to some treatments which affect in a different way male and female. The possibility of a gender-related difference in the oxidation of polyamines was investigated in rats by measuring the activity of polyamine oxidase, a ubiquitous enzyme of vertebrate tissues, which transforms spermine into spermidine and spermidine into putrescine. The study was carried out on thymus, spleen, kidney and liver of young rats of both sexes, and female rats showed a lower polyamine oxidase activity than male rats in all the tissues. We also found higher values of spermidine acetylation in female than male rats in thymus and liver. Owing to these gender-related differences, a higher spermidine N-acetyltransferase/polyamine oxidase ratio was found in female than in male rats. A second gender-related difference was a higher spermidine/spermine ratio in female than in male, the only exception being the thymus. These basal differences possibly account for the gender-related differences of polyamine metabolic enzyme activities in response to some treatments, including drugs or hormones.


Assuntos
Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Fatores Sexuais , Acetiltransferases/metabolismo , Aminoácidos/metabolismo , Animais , Feminino , Rim/enzimologia , Fígado/enzimologia , Masculino , Poliaminas/metabolismo , Ratos , Ratos Wistar , Baço/enzimologia , Timo/enzimologia , Distribuição Tecidual , Poliamina Oxidase
10.
Liver ; 18(5): 326-30, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9831361

RESUMO

AIMS/BACKGROUND: Given the important role of polyamines (putrescine, spermidine, spermine) in the modulation of macromolecular syntheses, gene expression and proteolysis, alterations in their metabolic pathways could be relevant during senescence. Since the few existing data address mainly polyamine biosynthesis, we studied the oxidative catabolism of polyamines in the liver of rats 3-36 months of age. METHODS: Polyamine oxidase activity was fluorimetrically measured using N1-acetylspermine as substrate. Spermidine/spermine N1-acetyltransferase and diamine oxidase were measured by radiochemical methods using labeled acetyl-coenzyme A and putrescine, respectively, as substrate. Polyamines were separated by HPLC and fluorimetrically quantified after post-column derivatization with o-phthaldialdehyde. RESULTS: Spermidine/spermine N1-acetyltransferase activity increased in 36-month-old rats and polyamine oxidase activity in 24- and 36-month-old rats. A decline in spermine and increases in spermidine and putrescine in elderly rats suggested an activation of the interconversion pathway of higher into lower polyamines. The activity of diamine oxidase, which degrades putrescine, was enhanced starting from 12 months of age. CONCLUSION: In the liver of aged rats, an increase in the catabolic enzymes leads to a reconversion of the higher polyamines to putrescine. This increased catabolism may represent an important age-related change and may contribute to impairment of the expression of growth-related genes in senescence.


Assuntos
Envelhecimento/metabolismo , Fígado/metabolismo , Poliaminas/metabolismo , Acetiltransferases/metabolismo , Amina Oxidase (contendo Cobre)/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Masculino , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo , Poliamina Oxidase
11.
Biochim Biophys Acta ; 1317(1): 15-8, 1996 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-8876622

RESUMO

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.


Assuntos
Acetiltransferases/metabolismo , Envelhecimento/metabolismo , Rim/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Poliaminas/metabolismo , Acetilação , Animais , Histonas/metabolismo , Masculino , Putrescina/metabolismo , Ratos , Ratos Wistar , Espermidina/análogos & derivados , Espermidina/metabolismo , Espermina/metabolismo , Especificidade por Substrato , Poliamina Oxidase
12.
Biochim Biophys Acta ; 1156(3): 291-4, 1993 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-8461319

RESUMO

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.


Assuntos
Acetiltransferases/metabolismo , Regeneração Hepática , Fígado/enzimologia , Acetiltransferases/antagonistas & inibidores , Animais , Ativação Enzimática , Masculino , Poliaminas/metabolismo , Ratos , Ratos Wistar
14.
Lab Invest ; 62(3): 297-304, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2314049

RESUMO

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.


Assuntos
Gastrectomia , Degeneração Neural , Ornitina Descarboxilase/metabolismo , Medula Espinal/enzimologia , Animais , Carboxiliases/biossíntese , Carboxiliases/metabolismo , Indução Enzimática , Ácido Fólico/sangue , Masculino , Poliaminas/metabolismo , Ratos , Ratos Endogâmicos , Medula Espinal/patologia , Vitamina B 12/sangue
15.
J Neurol Sci ; 89(1): 27-35, 1989 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2926440

RESUMO

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.


Assuntos
Adenosilmetionina Descarboxilase/metabolismo , Carboxiliases/metabolismo , Músculos/enzimologia , Distrofia Muscular Animal/enzimologia , Ornitina Descarboxilase/metabolismo , Animais , Di-Hidrotaquisterol , Masculino , Músculos/fisiopatologia , Distrofia Muscular Animal/induzido quimicamente , Ratos , Ratos Endogâmicos
17.
Res Commun Chem Pathol Pharmacol ; 56(3): 291-300, 1987 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3114844

RESUMO

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.


Assuntos
Reação de Fase Aguda/metabolismo , Inflamação/metabolismo , Fígado/metabolismo , Prostaglandinas E/biossíntese , Prostaglandinas F/biossíntese , Reação de Fase Aguda/induzido quimicamente , Animais , Aspirina/farmacologia , Dinoprosta , Dinoprostona , Indometacina/farmacologia , Fígado/efeitos dos fármacos , Masculino , Precursores de Ácido Nucleico/biossíntese , Precursores de RNA , RNA Mensageiro/biossíntese , Ratos , Ratos Endogâmicos , Terebintina
18.
Biochem Biophys Res Commun ; 143(3): 856-62, 1987 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-3105533

RESUMO

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.


Assuntos
Reação de Fase Aguda/enzimologia , Adenosilmetionina Descarboxilase/metabolismo , Carboxiliases/metabolismo , Inflamação/enzimologia , Fígado/enzimologia , Ornitina Descarboxilase/metabolismo , Animais , Ativação Enzimática/efeitos dos fármacos , Indometacina/farmacologia , Masculino , Masoprocol/farmacologia , Ratos , Ratos Endogâmicos
19.
J Natl Cancer Inst ; 76(6): 1217-21, 1986 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3458957

RESUMO

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.


Assuntos
Inosina/análogos & derivados , Neoplasias Hepáticas Experimentais/análise , Regeneração Hepática , Fígado/análise , Metiltioinosina/análise , Animais , Hepatectomia , Neoplasias Hepáticas Experimentais/induzido quimicamente , Masculino , Metildimetilaminoazobenzeno , Poliaminas/biossíntese , Ratos , Ratos Endogâmicos
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