Postoperative care in pediatric liver transplantation

In the last 25 years, liver transplantation in children has become an effective, definitive, and universally accepted treatment for terminal liver diseases. Long-term survival exceeds 80% and improves each year as the result of constant technical advancements and improvements in immediate postoperative intensive care and clinical control

Experiência em fístula artério-venosa para hemodiálise crônica em crianças: detalhes e refinamentos técnicos

PURPOSE: The aim of this paper is to report our experience in the creation of arteriovenous fistulas in children by using microsurgical vascular techniques, with emphasis on the details of the surgical technique. METHODS: The children underwent surgery from July 1997 to March 2004. Operating loupes (magnification: 3.5X) were used by the entire surgical team. After dissection and adequate mobilization, the vein was anastomosed to the artery in an end-to-lateral fashion by using 4 separate 7/0 or 8/0 prolene running sutures. RESULTS: Twenty nine children underwent 33 fistula creations - 21 radiocephalic, 6 brachiocephalic, 4 brachiobasilic, and 2 saphenofemoral. Primary patency was achieved in 17/21 (80.9%) of the radiocephalic fistulas, 5/6(83.3%) of the brachiocephalic, 3/4 (75.0%) of the brachiobasilic, and 2/2 (100%) of saphenofemoral. Two patients developed fistula occlusion and radial artery thrombosis, and in 2 others, radiocephalic fistulas became occluded in the first or second postoperative week. In the late postoperative period, the saphenofemoral fistulas were responsible for significant edema formation in the lower extremity; an aneurysm formed in a brachiocephalic fistula after a long period of utilization. As to the patency of the different sites of fistulas, the brachiocephalic and brachiobasilic fistulas had the same incidence of patency as the radiocephalic fistulas (P >;.05). CONCLUSIONS: This experience indicates that the arteriovenous fistulas are a satisfactory method for providing hemodialysis in children. The utilization of microsurgical techniques and some technical refinements herein described permit the attainment of high patency rates of the fistulas.OBJETIVO: Relatar a experiência dos autores na execução de fístulas artério-venosas em crianças, com a utilização dos recursos da microcirurgia vascular, com especial ênfase aos detalhes de técnica cirúrgica. MÉTODOS: Os pacientes foram operados entre julho de 1997 e março de 2004. Foram utilizadas lupas cirúrgicas (aumento de 3,5 vezes). Após a dissecção da veia e da artéria, a anastomose veno-arterial foi realizada de forma término-lateral, com quatro suturas contínuas de fio 7/0 ou 8/0. RESULTADOS: Vinte e nove crianças foram operadas para a realização de 33 fístulas - 21 rádio-cefálicas, 6 bráquio-cefálicas, 4 bráquio-basílicas e 2 safeno-femorais. Obteve-se permeabilidade em 17/21 (80,9%) fístulas rádio-cefálicas, 5/6 (83,3%) bráquio-cefálicas, 3/4 (75,0%) bráquio-basílicas e 2/2 (100%) safeno-femorais. 2 pacientes apresentaram obstrução da fístula e da artéria radial e 2 outras fístulas rádio-cefálicas obstruíram-se entre a primeira e segunda semana de pós-operatório. Tardiamente, verificou-se que as fístulas safeno-femorais causaram edema do membro inferior correspondente e houve formação de aneurisma em uma fístula bráquio-cefálica. Quanto à permeabilidade, verificou-se que as fístulas bráquio-cefálicas e bráquio-basílicas apresentaram a mesma incidência de permeabilidade em comparação com as fístulas rádio-cefálicas (p>;0,05). CONCLUSÃO: A presente casuística demonstra que as fístulas artério-venosas persistem como um bom acesso vascular para hemodiálise em crianças. A utilização de microcirurgia e alguns detalhes técnicos aqui descritos permitem a obtenção de bons índices de permeabilidade das fístulas

Identification of Monetary Policy Shocks in the Brazilian Market for Bank Reserves

We estimate an identified VAR (SVAR) with contemporaneous restrictions derived from a model of the market for bank reserves, which allows us to disentangle monetary policy shocks from demand shocks for reserves in Brazil. The main results are: i) the Central Bank of Brazil acts in order to smooth the bank reserve market interest rate (Selic); ii) the spread between the Selic rate and the discount rate provides information to estimate the demand curve for borrowed reserves; iii) overidentifying restrictions show that we cannot reject, for any period or model, the interest rate operational target hypothesis, even during the fixed exchange rate regime; iv) the impulse response functions show that shocks to the demand for reserves and to borrowed reserves generate statistically significant responses in real output and the inflation rate; v) all models display the liquidity effect and a small inflation rate puzzle.

Hipoplasia cardíaca em modelo animal de hérnia diafragmática congênita

PURPOSE: In previous papers, we described a new experimental model of congenital diaphragmatic hernia in rabbits, and we also reported noninvasive therapeutic strategies for prevention of the functional and structural immaturity of the lungs associated with this defect. In addition to lung hypoplasia, pulmonary hypertension, biochemical, and structural immaturity of the lungs, the hemodynamics of infants and animals with congenital diaphragmatic hernia are markedly altered. Hence, cardiac hypoplasia has been implicated as a possible cause of death in patients with congenital diaphragmatic hernia, and it is hypothesized to be a probable consequence of fetal mediastinal compression by the herniated viscera. Cardiac hypoplasia has also been reported in lamb and rat models of congenital diaphragmatic hernia. The purpose of the present experiment was to verify the occurrence of heart hypoplasia in our new model of surgically produced congenital diaphragmatic hernia in fetal rabbits. METHODS: Twelve pregnant New Zealand rabbits underwent surgery on gestational day 24 or 25 (normal full gestational time - 31 to 32 days) to create left-sided diaphragmatic hernias in 1 or 2 fetuses per each doe. On gestational day 30, all does again underwent surgery, and the delivered fetuses were weighed and divided into 2 groups: control (non-surgically treated fetuses) (n = 12) and congenital diaphragmatic hernia (n = 9). The hearts were collected, weighed, and submitted for histologic and histomorphometric studies. RESULTS: During necropsy, it was noted that in all congenital diaphragmatic hernia fetuses, the left lobe of the liver herniated throughout the surgically created defect and occupied the left side of the thorax, with the deviation of the heart to the right side, compressing the left lung; consequently, this lung was smaller than the right one. The body weights of the animals were not altered by congenital diaphragmatic hernia, but heart weights were decreased in comparison to control fetuses. The histomorphometric analysis demonstrated that congenital diaphragmatic hernia promoted a significant decrease in the ventricular wall thickness and an increase in the interventricular septum thickness. CONCLUSION: Heart hypoplasia occurs in a rabbit experimental model of congenital diaphragmatic hernia. This model may be utilized for investigations in therapeutic strategies that aim towards the prevention or the treatment of heart hypoplasia caused by congenital diaphragmatic hernia.OBJETIVO: Em trabalhos anteriores investigamos um novo modelo experimental de hérnia diafragmática congênita em coelhos e estudamos também métodos terapêuticos não invasivos para prevenir a imaturidade estrutural e funcional dos pulmões decorrente deste defeito. Além da hipoplasia pulmonar, hipertensão pulmonar, imaturidade bioquímica e estrutural dos pulmões, ocorrem alterações hemodinâmicas significativas em crianças com hérnia diafragmática congênita. Desta forma, hipoplasia cardíaca tem sido implicada como provável causa de óbito em crianças com hérnia diafragmática congênita, e interpretada provavelmente como conseqüência da compressão exercida pelas vísceras herniadas durante o desenvolvimento do feto. Este fenômeno tem sido relatado também em modelos experimentais de hérnia diafragmática congênita em fetos de ovelhas e ratos. O objetivo da presente experiência é o de verificar a ocorrência de hipoplasia cardíaca em nosso novo modelo de hérnia diafragmática congênita produzida com cirurgia em fetos de coelho. MÉTODOS: Doze coelhas prenhes foram operadas no 24º ou 25º dia de gestação (duração total da gestação -- 31 a 32 dias), com o objetivo de produzir hérnia diafragmática esquerda em um ou dois fetos em cada mãe. No 30º dia as coelhas foram novamente operadas para retirada dos fetos, que foram pesados e divididos em dois grupos: controle -- fetos não operados (n=12) e grupo com hérnia diafragmática (n=9). Os corações foram retirados, pesados e submetidos a estudos histológicos e histomorfométricos. RESULTADOS: Durante a necropsia verificou-se que em todos os fetos com hérnia diafragmática o lobo esquerdo do fígado sofreu herniação através do defeito produzido cirurgicamente e ocupou o lado esquerdo do tórax com desvio do coração para a direita, compressão do pulmão esquerdo e em conseqüência, este pulmão encontrava-se menor do que o direito. O peso total dos animais não sofreu alteração em decorrência da hérnia diafragmática, mas os pesos dos corações estavam diminuídos em comparação aos dos animais do grupo controle. Os estudos histomorfométricos demonstraram que a hérnia diafragmática provocou significativa redução na espessura da parede dos ventrículos e aumento da espessura do septo interventricular. CONCLUSÃO: Hipoplasia cardíaca ocorre em modelo de hérnia diafragmática congênita. Este modelo pode ser utilizado em investigações sobre métodos terapêuticos que tenham por objetivo prevenção ou tratamento da hipoplasia cardíaca decorrente da hérnia diafragmática congênita

RURAL-URBAN MIGRATION IN BOLIVIA: AN ESCAPE BOAT?

This paper studies rural-urban migration in Bolivia. Domestic migration usually works as an equalization mechanism, in which regions with fewer economic opportunities send migrants to more dynamic regions. We model the migration decision and take into account the possibility of self-selection for computing the returns to migration. We present selectivity corrected quantile regression models for earnings of both migrants and non-migrants in urban and metropolitan areas. We find that migrants receive a premium at low and median quantiles of the urban/metro conditional earnings distribution. This premium is somewhat diminished by a negative selectivity correction for migrants with lower probabilities of migration.

Explaining Bank Failures in Brazil: Micro, Macro and Contagion Effects (1994-1998)

We apply duration (survival) models with exponential hazard and exponential piecewise-constant hazard functions to study the determinants of bank failure over the period 1994 to 1998 in Brazil. The models deal empirically with left censoring in the data. We control for macroeconomic conditions and contagion effects, besides bank-specific factors. Our results indicate that foreign banks have distinct empirical survival functions relatively to other banks. For Brazil, macroeconomic and bank-level covariates explain the likelihood and timing of bank failure. Our indicator of system-wide financial fragility (IFF) suggests that the banking industry faced increased fragility after November 1995. We find evidence that the Program of Incentives to the Restructuring and Strengthening of the National Financial System (Proer) was able to distinguish solvent from insolvent banks.

Prognostic factors for the evolution and reversibility of chronic rejection in pediatric liver transplantation

OBJECTIVE: Chronic rejection remains a major cause of graft failure with indication for re-transplantation. The incidence of chronic rejection remains high in the pediatric population. Although several risk factors have been implicated in adults, the prognostic factors for the evolution and reversibility of chronic rejection in pediatric liver transplantation are not known. Hence, the current study aimed to determine the factors involved in the progression or reversibility of pediatric chronic rejection by evaluating a series of chronic rejection cases following liver transplantation. METHODS: Chronic rejection cases were identified by performing liver biopsies on patients based on clinical suspicion. Treatment included maintaining high levels of tacrolimus and the introduction of mofetil mycophenolate. The children were divided into 2 groups: those with favorable outcomes and those with adverse outcomes. Multivariate analysis was performed to identify potential risk factors in these groups. RESULTS: Among 537 children subjected to liver transplantation, chronic rejection occurred in 29 patients (5.4%). In 10 patients (10/29, 34.5%), remission of chronic rejection was achieved with immunosuppression (favorable outcomes group). In the remaining 19 patients (19/29, 65.5%), rejection could not be controlled (adverse outcomes group) and resulted in re-transplantation (7 patients, 24.1%) or death (12 patients, 41.4%). Statistical analysis showed that the presence of ductopenia was associated with worse outcomes (risk ratio=2.08, p=0.01). CONCLUSION: The presence of ductopenia is associated with poor prognosis in pediatric patients with chronic graft rejection