Neonatal hepatic drug elimination

After the transition from in utero to newborn life, the neonate becomes solely reliant upon its own drug clearance processes to metabolise xenobiotics. Whilst most studies of neonatal hepatic drug elimination have focussed upon in vitro expression and activities of drug-metabolising enzymes, the rapid physiological changes in the early neonatal period of life also need to be considered. There are dramatic changes in neonatal liver blood how and hepatic oxygenation due to the loss of the umbilical blood supply, the increasing portal vein blood flow, and the gradual closure of the ductus venosus shunt during the first week of life. These changes which may well affect the capacity of neonatal hepatic drug metabolism. The hepatic expression of cytochromes P450 1A2, 2C, 2D6, 2E1 and 3A4 develop at different rates in the postnatal period, whilst 3A7 expression diminishes. Hepatic glucuronidation in the human neonate is relatively immature at birth, which contrasts with the considerably more mature neonatal hepatic sulfation activity. Limited in vivo studies show that the human neonate can significantly metabolise xenobiotics but clearance is considerably less compared with the older infant and adult. The neonatal population included in pharmacological studies is highly heterogeneous with respect to age, body weight, ductus venosus closure and disease processes, making it difficult to interpret data arising from human neonatal studies. Studies in the perfused foetal and neonatal sheep liver have demonstrated how the oxidative and conjugative hepatic elimination of drugs by the intact organ is significantly increased during the first week of life, highlighting that future studies will need to consider the profound physiological changes that may influence neonatal hepatic drug elimination shortly after birth.

Role of myofibroblasts in tumour encapsulation of hepatocellular carcinoma in haemochromatosis

Background/Aims: Hepatocellular carcinoma is a carcinoma malignancy and a major complication of untreated haemochromatosis. Encapsulation of liver tumours has been associated with a better prognosis and longer disease-free periods following resection, This study investigated the source of the tumour capsule in patients with haemochromatosis and coexisting hepatocellular carcinoma and examined potential factors influencing development. Methods: Five haemochromatosis patients with encapsulated hepatocellular carcinoma were studied. Myofibroblasts were identified using combined immunohistochemistry and in situ hybridisation for a-smooth muscle actin and procollagen alpha (1)(I) mRNA, respectively. Immunohistochemistry was also performed for transforming growth factor (TGF)-beta (1), platelet-derived growth factor (PDGF)-beta receptor and malondialdehyde. Results. Procollagen alpha (1)(I) mRNA co-localised to alpha -smooth muscle actin positive myofibroblasts. The number of myofibroblasts was maximal within the capsule and decreased away from the tumour. TGF-beta (1) protein was expressed in iron-loaded cells in non-tumour liver at the interface of tumour capsule. PDGF-beta receptor expression was observed in mesenchymal cells in the tumour capsule and in portal tracts. Malondialdehyde adducts were observed in the tumour, non-tumour tissue and in the capsule. Conclusions: This study provides evidence that myofibroblasts are the cell type responsible for collagen production within the tumour capsule surrounding hepatocellular carcinoma in haemochromatosis, The production of TGF-beta (1) by iron-loaded hepatic cells at the tumour capsule interface may perpetuate the myofibroblastic phenotype, resulting in, the formation of the tumour capsule.

The spironolactone renaissance

Until recently, spironolactone was considered only as an antagonist at the aldosterone receptors of the epithelial cells of the kidney and was used clinically in the treatment of hyperaldosteronism and, occasionally, as a K+-sparing diuretic. The spironolactone renaissance started with the experimental finding that spironolactone reversed aldosterone-induced cardiac fibrosis by a cardiac action. Experimentally, spironolactone also has direct effects on blood vessels. Spironolactone reduces vascular fibrosis and injury, inhibits angiogenesis, reduces vascular tone and reduces portal hypertension. The rationale for the Randomized Aldactone Evaluation Study (RALES) of spironolactone in heart failure was that ‘aldosterone escape’ occurred through non-angiotensin II mechanisms. The RALES clinical trial was stopped early when it was shown that there was a 30% reduction in risk of death among the spironolactone patients. In RALES, spironolactone also reduced hospitalisation for worsening heart failure and improved the symptoms of heart failure. Other recent clinical trials have shown that spironolactone reduces cardiac and vascular collagen turnover, improves heart variability, reduces ventricular arrhythmias, improves endothelial dysfunction and dilates blood vessels in human heart failure and these effects probably all contribute to the increased survival in heart failure. Spironolactone may also be useful in the treatment of left ventricular hypertrophy, portal hypertension and cirrhosis. There have also been some recent small clinical trials of spironolactone as an anti-androgen showing potential in acne, hirsutism and precocious puberty.

Effects of dofetilide on cardiovascular tissues from normo- and hypertensive rats

The aim was to test whether dofetilide has some potential for use in the treatment of heart failure. Dofetilide at less than or equal to 3 x 10(-5) m had no effect on the quiescent Wistar Kyoto (WKY) rat aorta, mesenteric and intralobar arteries, or the spontaneous contractions of the WKY rat portal vein. Dofetilide at 10(-6) to 3 x 10(-5) m relaxed the KCl-contracted aorta. Dofetilide at 10(-9)-10(-7) m augmented the force of contraction of left ventricle strips from 12- and 18-month-old WKY rats at 2 Hz. Spontaneously hypertensive rats (SHRs) at 12 and 17-21 months of age are models of cardiac hypertrophy and failure, respectively. The augmentation of force at 2 Hz with dofetilide was similar on 12- and 18-month-old WKY rats and 12-month-old SHRs but reduced on the 18-month-old SHR left ventricle. At a higher more physiological frequency, 4 Hz, the threshold concentration of dofetilide required to augment the force responses of 21-month-old SHR left ventricles was markedly increased and the maximum augmenting effect was decreased. Dofetilide at 10(-7)-10(-5) m reduced the rate of the 17-month-old WKY rat right atrium, and had a similar effect on age-matched SHR right atrium. In summary, dofetilide is a positive inotrope and negative chronotrope in the rat. However, as the positive inotropic effect is not observed with clinically relevant concentrations at a physiological rate in heart failure, dofetilide is unlikely to be useful as a positive inotrope in the treatment of heart failure.

The therapeutic potential of endothelin-1 receptor antagonists and endothelin-converting enzyme inhibitors on the cardiovascular system

Clinical trials have established bosentan, an orally active non-selective endothelin (ET) receptor antagonist, as a beneficial treatment in pulmonary hypertension. Trials have also shown short-term benefits of bosentan in systemic hypertension and congestive heart failure. However, bosentan also increased plasma levels of ET-1, probably by inhibiting the clearance of ET-1 by endothelin type B (ET.) receptors, and this may mean its effectiveness is reduced with long-term clinical use. Preliminary data suggests that selective endothelin type A (ETA) receptor antagonists (BQ-123, sitaxsentan) may be more beneficial than the non-selective ET receptor antagonists in heart failure, especially when the failure is associated with pulmonary hypertension. Experimental evidence in animal disease models suggests that non-selective ET or selective ETA receptor antagonism may have a role in the treatment of athero-sclerosis, restenosis, myocarditis, shock and portal hypertension. In animal models of myocardial infarction and/or reperfusion injury, non-selective ET or selective ETA receptor antagonists have beneficial or detrimental effects depending on the conditions and agents used. Thus clinical trials of the nonselective ET or selective ETA receptor antagonists in these conditions are not presently warranted. Several selective endothelin-converting enzyme inhibitors tors have been synthesised recently, and these are only beginning to be tested in animal models of cardiovascular disease, and thus the clinical potential of these inhibitors is still to be defined.

Determination of regional flow by use of intravascular PET tracers: Microvascular theory and experimental validation for pig livers

Today, the standard approach for the kinetic analysis of dynamic PET studies is compartment models, in which the tracer and its metabolites are confined to a few well-mixed compartments. We examine whether the standard model is suitable for modern PET data or whether theories including more physiologic realism can advance the interpretation of dynamic PET data. A more detailed microvascular theory is developed for intravascular tracers in single-capillary and multiple-capillary systems. The microvascular models, which account for concentration gradients in capillaries, are validated and compared with the standard model in a pig liver study. Methods: Eight pigs underwent a 5-min dynamic PET study after O-15-carbon monoxide inhalation. Throughout each experiment, hepatic arterial blood and portal venous blood were sampled, and flow was measured with transit-time flow meters. The hepatic dual-inlet concentration was calculated as the flow-weighted inlet concentration. Dynamic PET data were analyzed with a traditional single-compartment model and 2 microvascular models. Results: Microvascular models provided a better fit of the tissue activity of an intravascular tracer than did the compartment model. In particular, the early dynamic phase after a tracer bolus injection was much improved. The regional hepatic blood flow estimates provided by the microvascular models (1.3 +/- 0.3 mL min(-1) mL(-1) for the single-capillary model and 1.14 +/- 0.14 min(-1) mL(-1) for the multiple-capillary model) (mean +/- SEM mL of blood min(-1) mL of liver tissue(-1)) were in agreement with the total blood flow measured by flow meters and normalized to liver weight (1.03 +/- 0.12 mL min(-1) mL(-1)). Conclusion: Compared with the standard compartment model, the 2 microvascular models provide a superior description of tissue activity after an intravascular tracer bolus injection. The microvascular models include only parameters with a clear-cut physiologic interpretation and are applicable to capillary beds in any organ. In this study, the microvascular models were validated for the liver and provided quantitative regional flow estimates in agreement with flow measurements.

Impulse-response function of splanchnic circulation with model-independent constraints: theory and experimental validation

Modeling physiological processes using tracer kinetic methods requires knowledge of the time course of the tracer concentration in blood supplying the organ. For liver studies, however, inaccessibility of the portal vein makes direct measurement of the hepatic dual-input function impossible in humans. We want to develop a method to predict the portal venous time-activity curve from measurements of an arterial time-activity curve. An impulse-response function based on a continuous distribution of washout constants is developed and validated for the gut. Experiments with simultaneous blood sampling in aorta and portal vein were made in 13 anesthetized pigs following inhalation of intravascular [O-15] CO or injections of diffusible 3-O[ C-11] methylglucose (MG). The parameters of the impulse-response function have a physiological interpretation in terms of the distribution of washout constants and are mathematically equivalent to the mean transit time ( T) and standard deviation of transit times. The results include estimates of mean transit times from the aorta to the portal vein in pigs: (T) over bar = 0.35 +/- 0.05 min for CO and 1.7 +/- 0.1 min for MG. The prediction of the portal venous time-activity curve benefits from constraining the regression fits by parameters estimated independently. This is strong evidence for the physiological relevance of the impulse-response function, which includes asymptotically, and thereby justifies kinetically, a useful and simple power law. Similarity between our parameter estimates in pigs and parameter estimates in normal humans suggests that the proposed model can be adapted for use in humans.

A model to investigate hepatic extraction of oxygen during anaesthesia in the dog

Measurement of hepatic oxygen extraction was performed on six healthy Greyhound dogs over a two hour period. The Greyhounds were anaesthetised and a right subcostal surgical incision performed. Ultrasonic flow transducers were used to measure flow rate in the hepatic artery and the portal vein. The blood oxygen tensions in arterial blood and in the portal and hepatic veins were also measured. Hepatic oxygen extraction remained stable throughout the study, despite a steady decline in arterial blood pressure. The methodology described in this study provides a direct measure of oxygen uptake by the liver in the dog and could readily be used to investigate hepatic uptake of drugs. (C) 2003 Elsevier Ltd. All rights reserved.

Boletim eletr??nico de bibliografias especializadas:comunica????o e lideran??a

A 4a edi????o do Boletim Eletr??nico de Bibliografias Especializadas apresenta publica????es do acervo da Biblioteca Graciliano Ramos e do Portal de Peri??dicos da ENAP. Este n??mero tem como foco o Programa de Comunica????o e Lideran??a (Comlide). Trata-se de uma iniciativa da ENAP, sob a responsabilidade da Diretoria de Desenvolvimento Gerencial (DDG), envolvendo todas as ??reas da Escola. As obras reunidas neste Boletim d??o ??nfase a t??cnicas de comunica????o e lideran??a dentro de organiza????es. O objetivo dessas estrat??gias ?? viabilizar o melhor desempenho em rela????o aos trabalhos em grupo. Com a crescente import??ncia de l??deres nas institui????es, estudos e projetos prop??em caminhos para que esses gestores motivem suas equipes a alcan??ar cada vez mais qualidade, produtividade e crescimento. Enfim, a colet??nea presente neste Boletim permite que se desenvolva uma melhor compreens??o quanto a conceitos e m??todos sugeridos por diversos autores, al??m de apresentar estudos de caso voltados para negocia????es e gest??o de equipes

A????es premiadas no 16?? Concurso Inova????o na Gest??o P??blica Federal 2011

Este livro re??ne as dez iniciativas premiadas no 16?? Concurso Inova????o na Gest??o P??blica Federal. Nesta 16?? edi????o, o Concurso conta com os apoios da Embaixada da Fran??a, da Embaixada da Noruega, da Ag??ncia de Coopera????o Internacional Alem?? (GIZ) e da Ag??ncia Brasileira de Coopera????o (ABC), que premiam os primeiros colocados com visitas t??cnicas. A ENAP tamb??m premia os vencedores com vagas nos cursos de Especializa????o em Gest??o P??blica e Desenvolvimento Gerencial , publica????es da Escola, livro contendo os relatos das iniciativas, certificado, divulga????o no Banco de Solu????es do s??tio do Concurso, assinatura de um ano da Revista do Servi??o P??blico (RSP) e Selo Inova????o

A????es premiadas no 14?? Concurso Inova????o na Gest??o P??blica Federal 2009

Nesta publica????o, referente ao 14?? Concurso Inova????o na Gest??o P??blica Federal, o leitor encontrar?? iniciativas inovadoras nas seguintes ??reas: Arranjos institucionais para coordena????o e/ou implementa????o de pol??ticas p??blicas (intra e inter-governamental); avalia????o e monitoramento de pol??ticas p??blicas; gest??o da informa????o; gest??o e desenvolvimento de pessoas; melhoria de processos de trabalho; planejamento, gest??o e desempenho institucional

A????es premiadas no 15?? Concurso Inova????o na Gest??o P??blica Federal 2010

Nesta publica????o, referente ao 15?? Concurso Inova????o na Gest??o P??blica Federal, o leitor encontrar?? iniciativas inovadoras nas seguintes ??reas: Arranjos institucionais para coordena????o e/ou implementa????o de pol??ticas p??blicas (intra e inter-governamental); atendimento ao cidad??o; gest??o da informa????o; melhoria dos processos de trabalho

Pol??ticas p??blicas para o tratamento da judicializa????o: janelas para solu????es alternativas

O panorama da judicializa????o das pol??ticas p??blicas (JPP) no Brasil se expande e se diversifica, imprimindo uma presen??a marcante na cena p??blica nacional. Isto tem levado atores da gest??o p??blica a buscarem solu????es alternativas para o tratamento da judicializa????o, quando esta bate ?? porta dos ??rg??os do Executivo, ou mesmo, quando entra sem bater. O presente trabalho visa transpor o debate pouco f??rtil que superdimensiona o papel do ativismo do Judici??rio, para situar a judicializa????o como fen??meno que carrega ao mesmo tempo problemas e janelas de solu????o para demandas cidad??s. Busca-se responder ?? indaga????o: o manejo da judicializa????o atrav??s de solu????es de gest??o para o atendimento de decis??es judiciais e para a preven????o de novos conflitos poderia ser considerado uma pol??tica p??blica? Para tal, ?? proposto um percurso anal??tico (te??rico e emp??rico). S??o confrontados dois campos te??ricos: a teoria da judicializa????o e os modelos anal??ticos de Pol??ticas P??blicas (m??ltiplos fluxos e equil??brio pontuado). A metodologia inclui o estudo de casos m??ltiplos da judicializa????o da Sa??de, por??m com pretens??es de aplica????o geral ?? JPP, mesmo que ainda explorat??ria. Com base na compara????o de casos, ?? constru??da uma tipologia de problemas e solu????es e testada a aplicabilidade dos fluxos de Kingdon (Problemas, Alternativas e Pol??tica) na forma????o da agenda do manejo da judicializa????o. S??o tamb??m estudados os aspectos do deslocamento de arena que a judicializa????o representaria, e da constru????o dessa arena emergente. Ao fim, os achados e possibilidades s??o postos em di??logo com a teoria da judicializa????o das pol??ticas p??blicas, buscando-se perceber as janelas para o estabelecimento de agendas de pol??ticas p??blicas mais sens??veis aos fluxos de judicializa????o

O caso da arte gr??fica Waj??pi e o embate contra a explora????o comercial inadequada: limites e potencialidades das pol??ticas p??blicas de prote????o ao patrim??nio imaterial

O presente estudo tem por finalidade discutir os limites e potencialidades dos instrumentos de pol??ticas p??blicas de prote????o ao patrim??nio imaterial, ?? luz das experi??ncias constitu??das em um caso concreto, qual seja, o registro da arte Kusiwa. Em 2003, a arte Kusiwa dos Waj??pi, no Amap?? recebeu o reconhecimento como Obra-Prima do Patrim??nio Oral e Imaterial da Humanidade, conferido pela UNESCO, um ano ap??s ter sido inscrita no Livro das Formas de Express??o e ter sido registrada pelo IPHAN. Entretanto, apesar dessas a????es de salvaguarda, esse patrim??nio imaterial vem sendo reiteradamente violado por meio do abuso comercial do uso n??o autorizado dos grafismos. O fato de as formas de produ????o e circula????o de conhecimento entre os coletivos ind??genas envolverem rela????es espec??ficas, que n??o se limitam ??s propostas atualmente dispon??veis na legisla????o sobre propriedade intelectual, confere um aspecto desafiador sobre a tem??tica. A partir do recorrente ass??dio da comercializa????o do Kusiwa, come??ou a haver um aprendizado institucional por parte do IPHAN e de diversos outros atores, principalmente quanto aos questionamentos envolvendo o alcance jur??dico de prote????o do patrim??nio dos bens registrados. Por tudo isso, o registro da arte Kusiwa foi o resultado de um processo mais amplo de conquistas de direitos e constru????o de cidadania, e gerou efeitos importantes n??o apenas para assegurar a transmiss??o intergeracional do conjunto de conhecimentos da cultura Waj??pi, mas, principalmente, porque a salvaguarda desse patrim??nio configurou-se como instrumento estrat??gico para o fortalecimento de a????es e lutas sociais que buscam assegurar a garantia de direitos culturais e at?? mesmo de direitos humanos de maneira ampla

Desafios da constru????o de uma pol??tica intersetorial de cultura e educa????o

A transi????o paradigm??tica vivenciada pela gest??o p??blica no Brasil tem provocado a busca por arranjos institucionais capazes de romper com a in??rcia institucional e responder ?? complexidade das novas demandas sociais. O presente estudo busca analisar a intersetorialidade a partir de fatores pol??ticos e institucionais que influenciaram o Programa Mais Educa????o, com foco na articula????o entre as ??reas de educa????o e cultura. Trata-se de pesquisa qualitativa realizada a partir do estudo sistem??tico da literatura sobre pol??ticas intersetoriais, analisada ?? luz do modelo sist??mico de Easton. Aborda conceitos como agendamento e implementa????o de pol??ticas p??blicas, centrando-se no debate contempor??neo sobre intersetorialidade. Analisa, a partir dos dados levantados sobre o Programa Mais Educa????o e entrevistas semi dirigidas com gestores dos diferentes minist??rios que o integram, mecanismos existentes na gest??o p??blica para que essa intersetorialidade se efetive. Constata a centralidade do papel das ideias na burocracia de governo em resposta a demandas sociais hist??ricas, contudo sorganizadas. O estudo reconhece a educa????o integral como um campo de atua????o complexo e interdisciplinar, cujo desenvolvimento de pol??ticas p??blicas mais efetivas, eficientes e eficazes, exige abordagens distintas e somat??ria de esfor??os entre as ??reas. A complexidade do modelo de gest??o do Programa reflete-se em um arranjo institucional inovador em que a intersetorialidade otimiza recursos e esfor??os das ??reas envolvidas, exigindo coordena????o intersetorial centralizada e coopera????o entre os ??rg??os