RESUMO
PURPOSE: To assess the long-term oncological outcomes in patients with locally advanced rectal cancer who underwent neoadjuvant therapy followed by local or total mesorectal excision. METHODS: Patients with locally advanced rectal adenocarcinoma who received neoadjuvant therapy from 2005 to 2017 were evaluated. Those with major or complete clinical response underwent a full-thickness local excision. Kaplan-Meier estimates were used to evaluate overall, disease-free, and local recurrence-free survival of patients who underwent local excision (LE group) and were compared with a matched cohort of patients who underwent total mesorectal excision (TME group). RESULTS: Among 252 patients who received neoadjuvant therapy for rectal cancer, 51 (20.2%) underwent a local excision. At a median follow-up of 61 months, patients who underwent local excision were stoma-free in 88.2% of cases and with rectum preserved in 78.5% of cases, respectively. The estimated 5-year local, disease-free, and overall survival was 91.8% vs 97.6% (95% CI: 79.5-96.8 vs 84.6-99.6), 86.7% vs 86.4% (95% CI: 72.5-93.9 vs 70.1-94.1), and 85% vs 90% (95% CI: 69.0-93.0% vs 75.3-96.2), in the study and matched control group, respectively. None of the differences was statistically significant. CONCLUSIONS: One-fifth of patients with locally advanced rectal cancer are manageable with a rectum-sparing approach after neoadjuvant therapy. With this strategy, about 80% patients will have their rectum preserved and 90% will be without stoma at long term.
Assuntos
Adenocarcinoma/terapia , Procedimentos Cirúrgicos do Sistema Digestório , Terapia Neoadjuvante , Neoplasias Retais/terapia , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Bases de Dados Factuais , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Procedimentos Cirúrgicos do Sistema Digestório/mortalidade , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante/efeitos adversos , Terapia Neoadjuvante/mortalidade , Recidiva Local de Neoplasia , Tratamentos com Preservação do Órgão , Estudos Prospectivos , Neoplasias Retais/mortalidade , Neoplasias Retais/patologia , Medição de Risco , Fatores de Risco , Estomas Cirúrgicos , Fatores de TempoRESUMO
AIM: Current follow-up guidelines for distant tumour recurrence after rectal cancer surgery are not defined or agreed. The aim was to elucidate the pattern of recurrence over time and provide information that could help direct a strategy for surveillance. METHOD: In all, 378 patients with locally advanced rectal cancer were treated with preoperative chemoradiotherapy and surgery with curative intent. Patients were followed up with a standard protocol, and data were prospectively collected in a dedicated database. Disease-free survival and overall survival were calculated. RESULTS: Within a median follow-up time of 75 months, rates of local and distant recurrence were 2.6% and 21.7%, respectively. Risk factors for recurrence were a baseline carcinoembryonic antigen > 5.0 ng/ml, a distance from the anal verge ≤ 5 cm, R1 resection margins, G3 grading, ypT staging > 2, positive lymph node status and a tumour regression grade of 3-5. Disease-free survival did not vary significantly between patients with lung and extra-pulmonary metastases (P = 0.59). The only factor associated with increased risk of lung metastases was a distance of the tumour from the anal verge of ≤ 5 cm (P = 0.01). Most recurrences occurred within the first 3 years after surgery (74.4%). The first site of recurrence was most frequently the lung (52.0%). The most frequent new primary malignancy was lung cancer (22.5%). CONCLUSIONS: Patients undergoing curative therapy for rectal cancer often experience distant recurrence; the majority of recurrences occur within the first 3 years after surgery and lung metastases are the most common. A predictive factor for pulmonary recurrence is a tumour in the lower rectum.
Assuntos
Quimiorradioterapia/estatística & dados numéricos , Terapia Neoadjuvante/estatística & dados numéricos , Recidiva Local de Neoplasia/epidemiologia , Neoplasias Retais/patologia , Reto/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Canal Anal/patologia , Canal Anal/cirurgia , Antígeno Carcinoembrionário/sangue , Bases de Dados Factuais , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Linfonodos/patologia , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Estudos Prospectivos , Neoplasias Retais/sangue , Neoplasias Retais/terapia , Reto/patologia , Fatores de Risco , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Rectum-sparing approaches appear to be appropriate in rectal cancer patients with a major (mCR) or complete clinical response (cCR) after neoadjuvant therapy. The aim of the present study is to evaluate the effectiveness of rectum-sparing approaches at 2 years after the completion of neoadjuvant treatment. STUDY DESIGN: Patients with rectal adenocarcinoma eligible to receive neoadjuvant therapy will be prospectively enrolled. Patients will be restaged 7-8 weeks after the completion of neoadjuvant therapy and those with mCR (defined as absence of mass, small mucosal irregularity no more than 2 cm in diameter at endoscopy and no metastatic nodes at MRI) or cCR will be enrolled in the trial. Patients with mCR will undergo local excision, while patients with cCR will either undergo local excision or watch and wait policy. The main end point of the study is to determine the percentage of rectum preservation at 2 years in the enrolled patients. CONCLUSION: This protocol is the first prospective trial that investigates the role of both local excision and watch and wait approaches in patients treated with neoadjuvant therapy for rectal cancer. The trial is registered at clinicaltrials.gov (NCT02710812).
Assuntos
Adenocarcinoma/terapia , Neoplasias Retais/terapia , Conduta Expectante , Adenocarcinoma/cirurgia , Quimiorradioterapia Adjuvante , Quimioterapia Adjuvante , Humanos , Terapia Neoadjuvante , Tratamentos com Preservação do Órgão , Período Pré-Operatório , Radioterapia Adjuvante , Neoplasias Retais/cirurgia , Reto , Projetos de PesquisaRESUMO
OBJECTIVES: Hypovitaminosis D is very common in the elderly in Italy and generally in the world, contributing to bone fractures and muscle weakness. The aim of the study was to evaluate bone metabolism in an old population of patients hospitalized not for musculo-skeletal complaints. METHODS: The clinical records of 175 patients, 98 female and 77 male, aged >65 years, hospitalized in a Department of Internal Medicine (Sacile, Western Friuli) were retrospectively reviewed. Serum levels of calcium, phosphorous, alkaline phosphatase, parathyroid hormone (PTH) and 25-OH vitamin D were evaluated. Correlations between these parameters were investigate. RESULTS: Abnormalities of bone metabolism parameters were frequently founded, particularly hypocalcemia, increased PTH and reduced 25-OH vitamin D. Hypovitaminosis D were detected in 88% of patients, low levels in 30.28% and very low levels in 57.72%. Hypovitaminosis D was related to female sex, old age of patients and high levels of PTH. CONCLUSIONS: Our data confirm that hypovitaminosis D is very common in elderly population. The study has been performed in an Italian Region where the supplementation of vitamin D in the elderly is not performed, suggesting that a awareness campaign of the doctors could be very useful to prevent bone metabolism abnormalities.
Assuntos
Deficiência de Vitamina D , Vitamina D , Fosfatase Alcalina , Cálcio , Humanos , Hormônio Paratireóideo , Deficiência de Vitamina D/epidemiologiaRESUMO
Negative symptoms of schizophrenia have a great impact on patients' functioning and are among the most important contributors to subject's disability. However, few studies have assessed the role of type and severity of symptomatology of schizophrenia on the psychiatric care resource utilization. We investigated if the clinical profile of patients at discharge from an index hospitalization might be associated with a different use of psychiatric care resources in the subsequent 1-year period in a large population of patients with schizophrenia spectrum disorders. Clinical records of 450 patients with schizophrenia spectrum disorders admitted in an acute psychiatric inpatient service and subsequently followed in the outpatient services of the same Department were reviewed. Patients with more severe negative symptoms at discharge from hospital showed a higher number and duration of hospitalizations in the 1-year follow-up, as well as a higher number of rehabilitative residential admissions than patients with milder severity of negative symptoms. The same was true for patients with predominant negative symptoms. A global resource utilization index indicated a higher use of psychiatric resources in patients with higher severity of negative symptoms. In conclusion, showing moderate to severe negative symptoms versus positive symptoms at discharge from a hospitalization for an acute exacerbation of schizophrenia spectrum disorder does predict a higher use of psychiatric care resources. This underlines the importance of relieving negative symptoms even in the acute phase of treatment and the need to develop more effective treatments for this symptom dimension.
Assuntos
Esquizofrenia , Seguimentos , Hospitalização , Humanos , Alta do Paciente , Estudos Retrospectivos , Esquizofrenia/epidemiologia , Esquizofrenia/terapiaRESUMO
A young woman suffering from S. pneumoniae meningitis developed intractable intracranial hypertension with a GCS of 3. Intracranial pressure (ICP) ranged above 30 mmHg despite maximal medical treatment and continuous CSF drainage. We performed a wide bilateral decompressive craniectomy (DC) with duraplasty and we observed an immediate and stable drop of her ICP. When discharged she was independent. DC has been rarely used to control ICP in encephalitis patients and recently only in one case of meningitis. This operation could be a valuable option when all other measures to decrease ICP have failed; when necessary, it should be performed according to some rules otherwise it could be harmful for the patient. Conclusive data on the impact of DC on the final outcome of such patients are not available yet.
Assuntos
Craniotomia , Descompressão Cirúrgica/métodos , Meningite Pneumocócica/complicações , Pseudotumor Cerebral/cirurgia , Adulto , Encéfalo/patologia , Feminino , Seguimentos , Humanos , Pressão Intracraniana/fisiologia , Imageamento por Ressonância Magnética , Meningite Pneumocócica/diagnóstico , Pseudotumor Cerebral/etiologia , Tomografia Computadorizada por Raios XRESUMO
B- and T-cell recirculation is crucial for the function of the immune system, with the control of cell migration being mainly mediated by several chemokines and their receptors. In this study, we investigated the expression and function of CXCR3 on normal and malignant B cells from 65 patients with chronic lymphoproliferative disorders (CLDs). Although CXCR3 is lacking on CD5(+) and CD5(-) B cells from healthy subjects, it is expressed on leukemic B lymphocytes from all (31/31) patients with chronic lymphocytic leukemia (CLL). The presence of CXCR3 was heterogeneous in other B-cell disorders, being expressed in 2 of 7 patients with mantle cell lymphoma (MCL), 4 of 12 patients with hairy cell leukemia (HCL), and 11 of 15 patients with other subtypes of non-Hodgkin's lymphomas (NHLs). Chemotaxis assay shows that normal B cells from healthy subjects do not migrate in response to IFN-inducible protein 10 (IP-10) and IFN-gamma-induced monokine (Mig). In contrast, a definite migration in response to IP-10 and Mig has been observed in all malignant B cells from patients with CLL, but not in patients with HCL or MCL (1/7 cases tested). Neoplastic B cells from other NHLs showed a heterogenous pattern. The migration elicited by IP-10 and Mig was inhibited by blocking CXCR3. No effect of IP-10 and Mig chemokines was observed on the cytosolic calcium concentration in malignant B cells. The data reported here demonstrate that CXCR3 is expressed on malignant B cells from CLDs, particularly in patients with CLL, and represents a fully functional receptor involved in chemotaxis of malignant B lymphocytes.
Assuntos
Linfócitos B/fisiologia , Quimiotaxia de Leucócito/fisiologia , Leucemia de Células Pilosas/patologia , Linfoma de Células B/patologia , Proteínas de Neoplasias/fisiologia , Células-Tronco Neoplásicas/fisiologia , Receptores de Quimiocinas/fisiologia , Adulto , Idoso , Linfócitos B/química , Cálcio/metabolismo , Quimiocina CXCL10 , Quimiocinas CXC/farmacologia , Quimiotaxia de Leucócito/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Interferon gama/farmacologia , Leucemia de Células Pilosas/metabolismo , Linfoma de Células B/metabolismo , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Células-Tronco Neoplásicas/química , Receptores CXCR3 , Receptores de Quimiocinas/biossíntese , Receptores de Quimiocinas/genéticaRESUMO
TNF-alpha is thought to play a pivotal role in the initiation and perpetuation of the chronic inflammatory process in rheumatoid arthritis. TNF-alpha blockers such as infliximab and etanercept are currently used in the treatment of active rheumatoid arthritis (RA) when traditional DMARDs have failed and are effective in a significant proportion of patients. However, about one third are non-responders to anti-TNF-alpha. The aim of this study was to verify whether rheumatoid patients, after failing infliximab, can benefit from etanercept. We analysed 18 patients with active RA with no response to at least 3 DMARDs and where infliximab therapy had failed. The patients had received infliximab associated with methotrexate: eleven of them did not show any significant response, while seven patients, after a good response, relapsed. Etanercept was then started. EULAR criteria of response were used with calculation of activity index DAS28 at baseline, after 2 weeks, 3 months and every third month until last follow-up. A moderate or good response was achieved with etanercept in 13 out of 18 patients. From our experience, etanercept can be considered as a good alternative choice when infliximab has failed.
Assuntos
Artrite Reumatoide/tratamento farmacológico , Imunoglobulina G/uso terapêutico , Fatores Imunológicos/uso terapêutico , Receptores do Fator de Necrose Tumoral/uso terapêutico , Adulto , Idoso , Anti-Inflamatórios/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Resistência a Medicamentos , Etanercepte , Feminino , Humanos , Imunoglobulina G/farmacologia , Fatores Imunológicos/farmacologia , Infliximab , Masculino , Pessoa de Meia-Idade , Falha de TratamentoRESUMO
The concentrations of putrescine, spermidine, and spermine in liver of rats fed on 4-dimethylaminoazobenzene and in the resultant hepatomas were found to be significantly higher than were those observed in normal liver from rats of the same strain, sex, and age. These modifications were due to the carcinogen and not to the special low-riboflavin diet used to obtain the carcinogenic effect of 4-dimethylaminoazobenzene. The first change observed during liver carcinogenesis was the early increase in the putrescine level, followed by an increase of spermidine and spermine, which reached maximum levels in growing hepatomas. A significant increase of urinary polyamines was also observed in tumor-bearing rats. Experiments on leucine incorporation into proteins of tissue slices, which were obtained from the same tissues on which polyamine determinations were carried out, showed that in rat liver carcinogenesis the rate of protein synthesis was well correlated with the polyamine levels. These results suggest that polyamines may play a role in the process of carcinogenesis and in tumor protein synthesis in vivo.
Assuntos
Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Proteínas de Neoplasias/biossíntese , Poliaminas/metabolismo , Lesões Pré-Cancerosas/metabolismo , p-Dimetilaminoazobenzeno , Animais , Carcinoma Hepatocelular/induzido quimicamente , Neoplasias Hepáticas/induzido quimicamente , Masculino , Neoplasias Experimentais/metabolismo , Poliaminas/fisiologia , Poliaminas/urina , Lesões Pré-Cancerosas/induzido quimicamente , Putrescina/metabolismo , Ratos , Espermidina/metabolismo , Espermina/metabolismoRESUMO
The antitumor activity of 2,3-dihydroxybutyraldehyde on Ehrlich carcinoma, Sarcoma 180, and Yoshida AH 130 hepatoma, as well as the aldehyde dehydrogenase activity in these tumors, was studied. 2,3-Dihydroxybutyraldehyde at nontoxic doses (500 mg/kg body weight i.p. daily for 7 days) slowed down the growth of solid and ascites tumors in mice. The treatment completely prevented the development of Yoshida ascites hepatoma in several rats. 2,3-Dihydroxybutyraldehyde, although it did not influence the growth of Ehrlich carcinoma transplanted in the brain of mice, significantly decreased in the lungs of these animals the number of viable tumour cells that derived from the primary tumor. All the tested tumors, which were sensitive to the action of 2,3-dihydroxybutyraldehyde, were virtually devoid of aldehyde dehydrogenase activity. These results suggest a possible relationship between the lack of this enzyme activity and the antitumor activity of aliphatic aldehydes.
Assuntos
Aldeídos/farmacologia , Antineoplásicos , Butileno Glicóis/farmacologia , Carcinoma de Ehrlich/tratamento farmacológico , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Sarcoma 180/tratamento farmacológico , Aldeído Oxirredutases/metabolismo , Aldeídos/toxicidade , Animais , Butileno Glicóis/toxicidade , Carcinoma de Ehrlich/enzimologia , Carcinoma Hepatocelular/enzimologia , Feminino , Neoplasias Hepáticas/enzimologia , Camundongos , Neoplasias Experimentais/tratamento farmacológico , Sarcoma 180/enzimologiaRESUMO
Diamine oxidase (EC 1.4.3.6) activity, measured as delta 1-[14C]pyrroline formation from [14C]putrescine, was studied in homogenates of regenerating liver and of 4-dimethylaminoazobenzene-induced by Yoshida AH 130 hepatomas of rat. The addition in the incubation medium of acetaldehyde increased delta 1-pyrroline formation in normal and regenerating liver that contained aldehyde dehydrogenase but not in hepatomas where this enzymatic activity was very low or virtually absent. Acetaldehyde did not modify the activity of a preparation of hog kidney diamine oxidase, while chloral hydrate and disulfiram, respectively, enhanced and depressed the activity of this enzyme. These results suggest that aldehyde-metabolizing enzymes present in homogenate may interfere with the amount of delta 1-pyrroline formation and that the use of acetaldehyde may give better information on tissue diamine oxidase activity. Diamine oxidase activity, which was very low in normal liver, increased rapidly in regenerating liver and reached maximum values between 16 and 48 hr after hepatectomy. A large increase in diamine oxidase activity, as compared to the values of normal liver, was also observed in 4-dimethylaminoazobenzene and Yoshida ascites hepatomas.
Assuntos
Amina Oxidase (contendo Cobre)/metabolismo , Neoplasias Hepáticas Experimentais/enzimologia , Regeneração Hepática , Fígado/enzimologia , Acetaldeído/farmacologia , Aldeído Desidrogenase , Aldeído Oxirredutases/antagonistas & inibidores , Amina Oxidase (contendo Cobre)/antagonistas & inibidores , Animais , Rim/enzimologia , Putrescina/metabolismo , Ratos , Suínos , p-DimetilaminoazobenzenoRESUMO
Several costimulatory molecules play a key role in the differentiation of B lymphocytes and in T-B-cell interactions. In this study, we addressed the question of whether different receptors and counter-receptors may be expressed on malignant B lymphocytes from chronic B-cell malignancies. Using flow cytometry and reverse transcription PCR analyses, the expression of molecules belonging to the tumor necrosis factor receptor (TNFR) and tumor necrosis factor ligand (TNFL) families, as well as the expression of CD80 and CD86 molecules, was analyzed in normal B cells and in different chronic lymphoproliferative disorders of B-cell type, including B-cell chronic lymphocytic leukemia (CLL), mantle cell lymphoma, hairy cell leukemia (HCL), and HCL variant. Different patterns of expression of TNFR and TNFL superfamily molecules were demonstrated among B-cell malignancies. In particular, CD40 was commonly observed on all B cells (both tumor and normal), whereas its ligand (CD40L), which is usually undetectable on resting normal B lymphocytes, was expressed in CLL and HCL but not in other chronic lymphoproliferative disorders. CD27 was not shown in normal B cells, although it was present in all malignancies and with particularly high density in mantle cell lymphoma. CD70 was widely distributed on tumor B lymphocytes, but not on the CD5+ normal counterpart. CD30 was strongly expressed in HCL variant and weakly in B-cell CLL, whereas its ligand showed a wide pattern of expression, including all neoplastic and normal B cells. TNFR II (CD120b) and CD80 were distributed on neoplastic B cells from all groups, usually at an intermediate to high degree of intensity, whereas the CD86 molecule was present at lower intensity than CD80. Finally, reverse transcription PCR analysis confirmed the presence of CD40L, CD30, and CD30L mRNAs in those B cells expressing the corresponding membrane-bound proteins at low density. Our data indicate that TNFR and TNFL molecules are of use clinically both in differentiating B-cell malignancies from the normal counterpart (i.e., CD27, CD70, CD40L, CD30, and CD80) and in defining different chronic B-cell disorders (i.e., CD40L, CD27, and CD30). Interestingly, the observation that several receptors and their ligands (i.e., CD40/CD40L, CD30/CD30L, and CD27/CD70) can be expressed on the same cell suggests that these molecules play a role in initiating and maintaining the neoplastic process by mediating B-T and B-B interactions.
Assuntos
Antígenos CD/análise , Linfócitos B/química , Leucemia Linfocítica Crônica de Células B/imunologia , Proteínas de Neoplasias/análise , Adulto , Feminino , Citometria de Fluxo , Humanos , Leucemia de Células Pilosas/imunologia , Masculino , Pessoa de Meia-Idade , Receptores do Fator de Necrose Tumoral/análiseRESUMO
BACKGROUND: Cooperatively-controlled robotic assistance could provide increased positional accuracy and stable and safe tissue targeting tasks during open-skull neurosurgical procedures, which are currently performed free-hand. METHODS: Two enhanced torque-based impedance control approaches, i.e. a variable damping criterion and a force-feedback enhancement control, were proposed in combination with an image-based navigation system. Control systems were evaluated on brain-mimicking phantoms by 13 naive users and 8 neurosurgeons (4 novices and 4 experts). RESULTS: In addition to a 60% reduction of user effort, the combination of the proposed strategies showed comparable performances with respect to state-of-the-art admittance controller, thus satisfying the clinical accuracy requirements (below 1 mm), reducing the hand tremor (by a factor of 10) and the tissue's indentation overshooting (by 80%). CONCLUSION: Although the perceived reliability of the system should be improved, the proposed control was suitable to assist targeting procedures, such as brain cortex stimulation, allowing for accurate, stable and safe contact with soft tissues. Copyright © 2015 John Wiley & Sons, Ltd.
Assuntos
Impedância Elétrica , Procedimentos Neurocirúrgicos/métodos , Crânio/cirurgia , Torque , Estudos de Avaliação como Assunto , Estudos de Viabilidade , Humanos , Procedimentos Cirúrgicos RobóticosRESUMO
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.
Assuntos
Acetiltransferases/metabolismo , Estradiol/farmacologia , Estro/metabolismo , Útero/enzimologia , Animais , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Feminino , Cinética , Ovariectomia , Poliaminas/metabolismo , Ratos , Ratos Endogâmicos , Especificidade por Substrato , Útero/efeitos dos fármacosRESUMO
The effect of ethanol on polyamine acetylation was studied in rat liver. Animals were fed on nutritionally complete liquid diets with 36% or 12% of total calories supplied as ethanol or isocaloric carbohydrates for 4 months. The diet with 36% calories as ethanol significantly increased the activity of cytosolic spermidine/spermine N1-acetyltransferase, the rate-limiting enzyme in polyamine interconversion. Such a stimulation did not appear in rats under the 12% ethanol regimen. The stimulation of spermidine/spermine N1-acetyltransferase was associated with increases in putrescine and spermidine concentrations, an appearance of N1-acetylspermidine, and a decrease in spermine. These results suggest that chronic ethanol intake stimulates the acetylation of polyamines and their interconversion in rat liver.
Assuntos
Consumo de Bebidas Alcoólicas/metabolismo , Alcoolismo/metabolismo , Fígado/metabolismo , Poliaminas/metabolismo , Acetilação , Acetiltransferases/metabolismo , Animais , Relação Dose-Resposta a Droga , Masculino , Putrescina/metabolismo , Ratos , Ratos Sprague-Dawley , Espermidina/análogos & derivados , Espermidina/metabolismo , Espermina/metabolismoRESUMO
The acute effect of ethanol on hepatic transglutaminase (EC 2.3.2.13) activity and polyamine levels were investigated in the rat. A high dose of ethanol (5 g/kg body weight, given by gastric intubation) caused in homogenate and cytosolic fraction an inhibition of 50-70% from 3 to 24 h which thereafter was reversible. Such a decrease may be in part responsible for the observed enhancement in putrescine and spermidine contents observed at the same times. Pyrazole, an inhibitor of alcohol dehydrogenase, prevented the ethanol-induced reduction in transglutaminase activity. Disulfiram, an inhibitor of aldehyde dehydrogenase, allowed detection of an inhibitory effect on enzyme activity even at a low dose of ethanol (2 g/kg), which per se did not modify transglutaminase activity. The hepatic cytosolic fraction, incubated in the presence of various concentrations of acetaldehyde, showed a dose-dependent inhibition of transglutaminase activity. All of these results suggest that acetaldehyde, the first and toxic metabolite of ethanol, inhibits hepatic transglutaminase activity, probably by its binding to the active thiol site of the enzyme. The reduction in transglutaminase may lead to an alteration of cytoskeleton, since the enzyme is known to be involved in tubuline polymerization and microfilament assembly.
Assuntos
Etanol/toxicidade , Fígado/enzimologia , Transglutaminases/análise , Animais , Dissulfiram/farmacologia , Inibidores Enzimáticos/farmacologia , Masculino , Pirazóis/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
The administration of preferential adrenergic receptor antagonists to uninephrectomized rats revealed the beta 2-adrenergic mediation in diamine oxidase activity increase that occurs in the remaining kidney undergoing compensatory hypertrophy. In fact, beta 1, beta 2- or beta 2, but not alpha 1-, alpha 2-, or beta 1-receptor-blocking agents prevented this enzyme enhancement. Further studies with adrenoceptor agonists, such as epinephrine (alpha 1, alpha 2, beta 1, beta 2), isoproterenol (beta 1, beta 2) or terbutaline (beta 2) showed that also in normal rat kidney diamine oxidase activity is under the control of catecholamine-beta 2-receptors through a mechanism that involves new synthesis of mRNA and protein. Theophylline, an inhibitor of phosphodiesterase, or forskolin, an activator of adenyl cyclase, increased diamine oxidase activity as does epinephrine or nephrectomy. Thus, catecholamine-triggered beta 2-receptors coupled to adenyl cyclase are involved in the regulation of diamine oxidase activity in normal and hypertrophic rat kidney.
Assuntos
Amina Oxidase (contendo Cobre)/metabolismo , Rim/metabolismo , Receptores Adrenérgicos beta/metabolismo , Agonistas Adrenérgicos/farmacologia , Animais , Colforsina , Diterpenos/farmacologia , Hipertrofia , Rim/patologia , Masculino , Ratos , Ratos Endogâmicos , Receptores Adrenérgicos beta/efeitos dos fármacos , Simpatolíticos/farmacologia , Teofilina/farmacologiaRESUMO
Polyamine levels and diamine oxidase (EC 1.4.3.6) activity were studied in hypertrophic heart of spontaneously hypertensive rats as well as in the heart of Wistar rats during the development and regression of cardiac hypertrophy induced by isoproterenol administration. In spontaneously hypertensive rats, putrescine content and diamine oxidase activity were higher than those found in normotensive Kyoto-Wistar control rats. During the development of cardiac hypertrophy induced by isoproterenol, there was an increase in polyamine content and diamine oxidase activity. The administration of cycloheximide or actinomycin D prevented the increase in diamine oxidase activity during the first 24 h after isoproterenol administration, demonstrating that the rise in diamine oxidase activity was due to synthesis of new enzyme. Following the cessation of isoproterenol treatment, cardiac hypertrophy regressed and polyamine levels and diamine oxidase activity diminished toward control values. The administration of aminoguanidine to isoproterenol-treated rats caused in the heart an inhibition of diamine oxidase activity that led to an increase in putrescine level beyond the values found in animals given isoproterenol alone. The results suggest that the enhancement of diamine oxidase activity plays a role in the regulation of putrescine level in hypertrophic heart.
Assuntos
Amina Oxidase (contendo Cobre)/metabolismo , Cardiomegalia/metabolismo , Hipertensão/metabolismo , Isoproterenol/farmacologia , Poliaminas/metabolismo , Animais , Masculino , Proteínas Musculares/metabolismo , Miocárdio/metabolismo , Tamanho do Órgão/efeitos dos fármacos , Putrescina/metabolismo , Ratos , Ratos Endogâmicos , Fatores de TempoRESUMO
The synthesis and turnover of diamine oxidase (EC 1.4.3.6) activity was studied in regenerating rat liver after partial hepatectomy using inhibitors of protein and RNA syntheses. The administration to animals of cycloheximide or actinomycin D prevented the increase in diamine oxidase activity normally observed during the first hours after hepatectomy. The study of the turnover rate of diamine oxidase with cycloheximide demonstrated that the half-life of this enzyme was about 15 h in normal and regenerating liver. These results suggest that the rise in diamine oxidase activity in regenerating rat liver was due to the synthesis of new enzyme rather than to a lengthening of its turnover.
Assuntos
Amina Oxidase (contendo Cobre)/metabolismo , Regeneração Hepática , Fígado/enzimologia , Amina Oxidase (contendo Cobre)/genética , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Indução Enzimática , Meia-Vida , Cinética , Fígado/efeitos dos fármacos , Regeneração Hepática/efeitos dos fármacosRESUMO
Diamine oxidase (EC 1.4.3.6) activity, measured as [14C]delta1 -pyrroline formation from [14C]putrescine, was studied in homogenates of rat kidney during compensatory hypertrophy after unilateral nephrectomy. Acetaldehyde and to a lesser degree phenobarbital, at concentrations which did not modify the activity of a preparation of hog kidney diamine oxidase, increased delta1 -pyrroline formation in kidney homogenate, which suggests that aldehyde-metabolizing enzymes present in this tissue may interfere with the yield of delta1 -pyrroline formation and that the use of acetaldehyde may give better information on kidney diamine oxidase activity. Other inhibitors of aldehyde-metabolizing enzymes such as chloral hydrate, disulfiram, and pyrazole cannot be used for diamine oxidase determination since they stimulated or depressed this enzyme activity. In rat kidney undergoing compensatory hypertrophy the levels of putrescine, spermidine, and spermine increased rapidly and were followed by an increase in diamine oxidase activity that presented a first peak on day 2 and a second peak on day 6. The administration of cycloheximide or actinomycin D to nephrectomized rates prevented the increase in diamine oxidase activity. The study of the turnover rate of diamine oxidase with cycloheximide demonstrated that the half-life of this enzyme was about 14 h in normal and hypertrophic kidney. The results suggest that the increase in diamine oxidase activity in renal hypertrophy was due to the synthesis of new enzymes rather than to slowing of its degradation.