RESUMO
Nonadherence to immunosuppressant medications is a leading cause of poor long-term outcomes in transplant recipients. The Medication Level Variability Index (MLVI) provides a vehicle for transplant outcome risk-stratification through continuous assessment of adherence. The MALT (Medication Adherence in children who had a Liver Transplant) prospective multi-site study evaluated whether MLVI predicts late acute rejection (LAR). Four hundred pediatric (1-17-year-old) liver transplant recipients were enrolled and followed for 2 years. The a-priori hypothesis was that a higher MLVI predicts LAR. Predefined secondary analyses evaluated other outcomes such as liver enzyme levels, and sensitivity analyses compared adolescents to pre-adolescents. In the primary analysis sample of 379 participants, a higher prerejection MLVI predicted LAR (mean prerejection MLVI with LAR: 2.4 [3.6 standard deviation] versus without LAR, 1.6 [1.1]; p = 0.026). Fifty-three percent of the adolescents with MLVI>2 in year 1 had LAR by the end of year 2, as compared with 6% of those with year 1 MLVI≤2. A higher MLVI was significantly associated with all secondary outcomes. MLVI, a marker of medication adherence that uses clinically derived information, predicts LAR in pediatric liver transplant recipients.
Assuntos
Imunossupressores/administração & dosagem , Transplante de Fígado , Cooperação do Paciente , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Rejeição de Enxerto , Humanos , Imunossupressores/sangue , Lactente , Estudos Prospectivos , Tacrolimo/administração & dosagem , Tacrolimo/sangue , Resultado do TratamentoRESUMO
The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.
Assuntos
Rejeição de Enxerto/etiologia , Rejeição de Enxerto/patologia , Isoanticorpos/imunologia , Transplante de Fígado/efeitos adversos , Aloenxertos , Humanos , Relatório de PesquisaRESUMO
In a cross-sectional study, we assessed effects of calcineurin inhibitor (CNI) or rapamycin on T-regulatory (Treg) cells from children with stable liver (n = 53) or kidney (n = 9) allografts several years posttransplant. We analyzed Treg number, phenotype, suppressive function, and methylation at the Treg-specific demethylation region (TSDR) using Tregs and peripheral blood mononuclear cells. Forty-eight patients received CNI (39 as monotherapy) and 12 patients received rapamycin (9 as monotherapy). Treg numbers diminished over time on either regimen, but reached significance only with CNI (r =-0.424, p = 0.017). CNI levels inversely correlated with Treg number (r =-0.371, p = 0.026), and positively correlated with CD127+ expression by Tregs (r = 0.437, p = 0.023). Patients with CNI levels >3.6 ng/mL had weaker Treg function than those with levels <3.6 ng/mL, whereas rapamycin therapy positively correlated with Treg numbers (r = 0.628, p = 0.029) and their expression of CTLA4 (r = 0.726, p = 0.041). Overall, CTLA4 expression, TSDR demethylation and an absence of CD127 were important for Treg suppressive function. We conclude that rapamycin has beneficial effects on Treg biology, whereas long-term and high dose CNI use may impair Treg number, function and phenotype, potentially acting as a barrier to attaining host hyporesponsiveness to an allograft.
Assuntos
Calcineurina/uso terapêutico , Rejeição de Enxerto/imunologia , Imunossupressores/uso terapêutico , Transplante de Rim/imunologia , Transplante de Fígado/imunologia , Sirolimo/uso terapêutico , Linfócitos T Reguladores/efeitos dos fármacos , Adolescente , Estudos de Casos e Controles , Criança , Estudos Transversais , Feminino , Seguimentos , Fatores de Transcrição Forkhead/metabolismo , Humanos , Leucócitos Mononucleares/imunologia , Masculino , Prognóstico , Linfócitos T Reguladores/imunologia , Transplante HomólogoRESUMO
Though robust clinical data are available within transplantation, these data are not used for broad-based, multicentered quality improvement initiates. This article describes a targeted quality improvement initiative within the Studies of Pediatric Liver Transplantation (SPLIT) Registry. Using standard statistical techniques and clinical expertise to adjust for data and statistical reliability, we identified the pediatric liver transplant centers in North America with the lowest hepatic artery thrombosis rate and biliary complication rates. A survey was completed to establish current practices within the entire SPLIT group. Surgeons from the highest performing centers presented a detailed, technically oriented overview of their current practices. The presentations and discussion that followed were recorded and form the basis of the best practices described herein. We frame this work as a unique six-step approach roadmap that may serve as an efficient and cost effective model for novel broad-based quality improvement initiatives within transplantation.
Assuntos
Transplante de Fígado/efeitos adversos , Complicações Pós-Operatórias/prevenção & controle , Benchmarking , Criança , Artéria Hepática/patologia , Humanos , Disseminação de Informação , América do Norte , Trombose/prevenção & controleRESUMO
This multicenter study examined prevalence of cognitive and academic delays in children following liver transplant (LT). One hundred and forty-four patients ages 5-7 and 2 years post-LT were recruited through the SPLIT consortium and administered the Wechsler Preschool and Primary Scale of Intelligence, 3rd Edition (WPPSI-III), the Bracken Basic Concept Scale, Revised (BBCS-R), and the Wide Range Achievement Test, 4th edition (WRAT-4). Parents and teachers completed the Behavior Rating Inventory of Executive Function (BRIEF). Participants performed significantly below test norms on intelligence quotient (IQ) and achievement measures (Mean WPPSI-III Full Scale IQ = 94.7 ± 13.5; WRAT-4 Reading = 92.7 ± 17.2; WRAT-4 Math = 93.1 ± 15.4; p < 0001). Twenty-six percent of patients (14% expected) had 'mild to moderate' IQ delays (Full Scale IQ = 71-85) and 4% (2% expected) had 'serious' delays (Full Scale IQ ≤ 70; p < 0.0001). Reading and/or math scores were weaker than IQ in 25%, suggesting learning disability, compared to 7% expected by CDC statistics (p < 0.0001). Executive deficits were noted on the BRIEF, especially by teacher report (Global Executive Composite = 58; p < 0.001). Results suggest a higher prevalence of cognitive and academic delays and learning problems in pediatric LT recipients compared to the normal population.
Assuntos
Cognição , Escolaridade , Transplante de Fígado/efeitos adversos , Transplante de Fígado/psicologia , Criança , Pré-Escolar , Transtornos Cognitivos/etiologia , Estudos de Coortes , Função Executiva , Feminino , Humanos , Testes de Inteligência , Deficiências da Aprendizagem/etiologia , Estudos Longitudinais , Masculino , Psicometria , Sistema de Registros , Estados UnidosRESUMO
Impaired kidney function is a well-recognized complication following liver transplantation (LT). Studies of this complication in children have been limited by small numbers and insensitive outcome measures. Our aim was to define the prevalence of, and identify risk factors for, post-LT kidney dysfunction in a multicenter pediatric cohort using measured glomerular filtration rate (mGFR). We conducted a cross-sectional study of 397 patients enrolled in the Studies in Pediatric Liver Transplantation (SPLIT) registry, using mGFR < 90 mL/min/1.73 m(2) as the primary outcome measure. Median age at LT was 2.2 years. Primary diagnoses were biliary atresia (44.6%), fulminant liver failure (9.8%), metabolic liver disease (16.4%), chronic cholestatic liver disease (13.1%), cryptogenic cirrhosis (4.3%) and other (11.8%). At a mean of 5.2 years post-LT, 17.6% of patients had a mGFR < 90 mL/min/1.73 m(2) . In univariate analysis, factors associated with this outcome were transplant center, age at LT, primary diagnosis, calculated GFR (cGFR) at LT and 12 months post-LT, primary immunosuppression, early post-LT kidney complications, age at mGFR, height and weight Z-scores at 12 months post-LT. In multivariate analysis, independent variables associated with a mGFR <90 mL/min/1.73 m(2) were primary immunosuppression, age at LT, cGFR at LT and height Z-score at 12 months post-LT.
Assuntos
Taxa de Filtração Glomerular , Falência Renal Crônica/etiologia , Transplante de Fígado/efeitos adversos , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Imunossupressores/efeitos adversos , Lactente , Masculino , Estudos Prospectivos , Resultado do TratamentoRESUMO
In an open-label, prospective, pharmacokinetic assessment, we evaluated total drug exposure (area under the curve [AUC]) of intravenous (IV) ganciclovir (GCV) and oral (p.o.) valganciclovir when normalized for body surface area (BSA) in pediatric liver (n=20) and renal (n=26) transplant patients Reference doses for IV GCV (200 mg/m(2)) and p.o. valganciclovir (520 mg/m(2)) were based on adult doses, and adjusted for BSA initially, and BSA and renal function (estimated via creatinine clearance [CrCL]) thereafter. Renal transplant patients received GCV on days 1-2, valganciclovir 260 mg/m(2) on day 3, and valganciclovir 520 mg/m(2) on day 4. Liver transplant patients received twice daily GCV from enrollment to day 12, and then valganciclovir twice daily on days 13-14. GCV pharmacokinetics were described using a population pharmacokinetic approach. Type of solid organ transplant (kidney or liver) had no effect on GCV pharmacokinetics. Median GCV exposure following valganciclovir 520 mg/m(2) was similar to that with IV GCV, and to that reported in adults. Patients <5 years of age had AUC values approximately 50% of those compared with older age ranges; dosing based on both BSA and CrCL increased drug exposure in younger patients. A dosing algorithm based on BSA and CrCL should be tested in future studies.
Assuntos
Antivirais/farmacocinética , Infecções por Citomegalovirus/prevenção & controle , Ganciclovir/análogos & derivados , Ganciclovir/farmacocinética , Transplante de Rim/efeitos adversos , Transplante de Fígado/efeitos adversos , Administração Oral , Adolescente , Adulto , Algoritmos , Antivirais/administração & dosagem , Antivirais/uso terapêutico , Área Sob a Curva , Superfície Corporal , Criança , Pré-Escolar , Creatinina/sangue , Relação Dose-Resposta a Droga , Feminino , Ganciclovir/administração & dosagem , Ganciclovir/uso terapêutico , Humanos , Lactente , Injeções Intravenosas , Masculino , Valganciclovir , Adulto JovemRESUMO
The objective was to review the current state of knowledge and recommend future research directions related to long-term outcomes for pediatric liver transplant recipients. A 1-day Clinical Research Workshop on Improving Long-Term Outcomes for Pediatric Liver Transplant Recipients was held on February 12, 2007, in Washington, DC. The speaker topics were germane to research priorities delineated in the chapters on Pediatric Liver Diseases and on Liver Transplantation in the Trans-NIH Action Plan for Liver Disease Research. Issues that compromise long-term well-being and survival but are amenable to existing and new research efforts were presented and discussed. Areas of research that further enhanced the research priorities in the Action Plan for Liver Disease Research included collection of longitudinal data to define emerging trends of clinical challenges; identification of risk factors associated with long-term immunosuppression complications; development of tolerance-inducing regimens; definition of biomarkers that reflect the level of clinical immunosuppression; development of instruments for the measurement of health wellness; identification of risk factors that impede growth and intellectual development before and after liver transplantation and identification of barriers and facilitators that impact nonadherence and transition of care for adolescents.
Assuntos
Transplante de Fígado , Avaliação de Resultados em Cuidados de Saúde/tendências , Pediatria/tendências , Adolescente , Criança , Pré-Escolar , Sobrevivência de Enxerto/imunologia , Humanos , Terapia de Imunossupressão/efeitos adversos , Lactente , Recém-Nascido , Transplante de Fígado/efeitos adversos , Transplante de Fígado/imunologia , Transplante de Fígado/mortalidade , Prognóstico , Qualidade de Vida , Fatores de Risco , Análise de SobrevidaRESUMO
Binding of 125I-labeled epidermal growth factor (EGF) was characterized in basolateral plasma membranes prepared from the livers of 21-day gestation fetuses, 14-day-old sucklings and adult Sprague-Dawley rats using a self-generating Percoll gradient method. The membrane preparations employed have been previously assayed in terms of plasma membrane protein yield, enrichment of various marker enzymes and sodium-dependent bile acid and amino acid transport. 125I-EGF binding was saturable and time and temperature dependent. Equilibrium analyses showed that the suckling period is characterized by a marked decrease in overall hepatic EGF binding capacity (460 +/- 50 fmol/mg protein) compared to either the fetal period (1290 +/- 160 fmol/mg) or to adults of either sex (males = 1540 +/- 230, females 1010 +/- 130 fmol/mg). Treatment of the suckling rat with parenteral EGF resulted in a 78% reduction in the observed binding capacity when assessed 2 h after growth factor administration. Comparison of binding affinities revealed no significant difference between the suckling and adult preparations (Kd = 0.40 +/- 0.03 vs. 0.39 +/- 0.02 nM, respectively); however, both preparations differed significantly from the fetal group which exhibited a decreased affinity of binding with a higher overall dissociation constant (Kd = 0.68 +/- 0.06 nM). Thus, it appears that major ontogenetic changes occur in the rat hepatic ligand/receptor system for epidermal growth factor. These changes are discussed in the context of transitional events in mammalian development such as birth and weaning.
Assuntos
Animais Lactentes/metabolismo , Receptores ErbB/metabolismo , Feto/metabolismo , Fígado/crescimento & desenvolvimento , Animais , Membrana Celular/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Receptores ErbB/efeitos dos fármacos , Feminino , Cinética , Fígado/embriologia , Fígado/metabolismo , Masculino , Ratos , Ratos Endogâmicos , Caracteres SexuaisRESUMO
We report the cloning of a 2.2 kb cDNA encoding a Na(+)-and Cl- dependent betaine/GABA (gamma-aminobutyric acid) transporter from rat liver poly(A+) RNA. 5'-RACE revealed an additional 355 bases 5' to the 2.2 kb cDNA sequence. Northern analysis demonstrated two (2.2 kb and 2.6 kb) mRNA isoforms in rat liver. Betaine transporter mRNA was also detected in the brain, spleen, lung, and kidney using the 2.2 kb cDNA clone as a probe. Only the 2.6 kb mRNA from the liver hybridized with the 5'-RACE product.
Assuntos
Proteínas de Transporte/genética , DNA Complementar/genética , Fígado/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Betaína/metabolismo , Proteínas de Transporte/metabolismo , Clonagem Molecular , Proteínas da Membrana Plasmática de Transporte de GABA , Dados de Sequência Molecular , Especificidade de Órgãos , Ratos , Análise de Sequência de DNA , XenopusRESUMO
The purpose of this study was to assess GH sensitivity in children with Alagille syndrome (syndromic intrahepatic bile duct paucity) by examining their response to short term administration of recombinant human GH (rhGH). Serum levels of insulin-like growth factor-I (IGF-I) were low despite elevated overnight integrated serum GH concentrations. Administration of rhGH (0.05 mg/kg.day for 3 days) to four growth-retarded children with Alagille syndrome did not significantly alter the serum concentrations of IGF-I and insulin, blood urea nitrogen, or urinary calcium excretion. In contrast, circulating IGF-I increased 2-fold in two children with Alagille syndrome and normal stature. In the control group, consisting of seven prepubertal children with GH deficiency, the predicted changes in response to rhGH in serum concentrations of IGF-I and insulin, urea nitrogen, and urinary calcium excretion were observed. Serum GH-binding protein levels, measured by a ligand-mediated immunofunctional assay, were significantly higher in children with Alagille syndrome than in children with cirrhosis or GH deficiency. We conclude that growth-retarded children with Alagille syndrome are insensitive to GH. The growth disturbances and metabolic defects may be due in part to failure to increase IGF-I concentrations in response to GH, implying that growth-retarded children with Alagille syndrome may benefit from IGF-I treatment.
Assuntos
Síndrome de Alagille/sangue , Síndrome de Alagille/fisiopatologia , Proteínas de Transporte/sangue , Transtornos do Crescimento/sangue , Transtornos do Crescimento/fisiopatologia , Hormônio do Crescimento/farmacologia , Síndrome de Alagille/complicações , Nitrogênio da Ureia Sanguínea , Cálcio/urina , Criança , Pré-Escolar , Resistência a Medicamentos , Feminino , Transtornos do Crescimento/complicações , Hormônio do Crescimento/sangue , Hormônio do Crescimento/deficiência , Humanos , Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , Masculino , Proteínas Recombinantes , Valores de ReferênciaRESUMO
Type III glycogen-storage disease (GSD-III), due to decreased activity of the glycogen debranching enzyme amylo-1,6 glucosidase, may cause hepatic dysfunction, growth failure, and myopathy. The prevention of hypoglycemia by nocturnal intragastric formula infusion has been shown to enhance growth and improve the metabolic abnormalities associated with GSD-III. Cornstarch therapy was effective in preventing hypoglycemia in a few patients with GSD-III who were previously treated with nocturnal enteral formula infusion, but oral cornstarch had not been evaluated as an initial treatment. We studied three patients with GSD-III who exhibited growth failure, elevated serum aminotransferase concentrations, and asymptomatic hypoglycemia. Cornstarch therapy was associated with maintenance of normoglycemia, increased growth velocity, and decreased serum aminotransferase concentrations in all patients. Our experience suggests that cornstarch therapy can be effective as an initial treatment for patients with GSD-III.
Assuntos
Doença de Depósito de Glicogênio Tipo III/tratamento farmacológico , Doença de Depósito de Glicogênio/tratamento farmacológico , Amido/uso terapêutico , Zea mays , Glicemia/análise , Criança , Desenvolvimento Infantil , Pré-Escolar , Feminino , Doença de Depósito de Glicogênio Tipo III/sangue , Doença de Depósito de Glicogênio Tipo III/fisiopatologia , Humanos , Fígado/patologia , Masculino , Transaminases/sangue , Aumento de PesoRESUMO
BACKGROUND: Successful clinical application of hepatocyte transplantation has been limited by poor engraftment of the recipient liver by transplanted hepatocytes. METHODS: To address the hypothesis that liver regeneration induced by an acute hepatotoxic injury promotes expansion of transplanted hepatocytes, we injected beta-galactosidase-labeled hepatocytes intrasplenically into mice 24 hr after treatment with carbon tetrachloride (CCl4) and into untreated controls. RESULTS: Macroscopic examination of whole liver segments identified clusters of transplanted hepatocytes uniformly spread on the capsular surface of the recipient liver and in the liver core following the distribution pattern of portal vein branches. Frozen sections showed that although the degree of initial engraftment of transplanted hepatocytes was similar in CCl4-treated and control livers, there was a fourfold increase of engrafted hepatocytes in CCl4-treated livers 10 days after transplantation which persisted to 28 days. CONCLUSIONS: We conclude that the number of transplanted hepatocytes increases in response to regeneration signal triggered by an acute hepatocyte-specific liver injury.
Assuntos
Intoxicação por Tetracloreto de Carbono/patologia , Transplante de Células , Fator de Crescimento de Hepatócito/biossíntese , Regeneração Hepática , Fígado/citologia , Animais , Sobrevivência de Enxerto/fisiologia , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , RNA Mensageiro/biossíntese , Baço , Fatores de Tempo , Transcrição Gênica , Transfecção , Transplante Heterotópico , beta-Galactosidase/biossínteseRESUMO
OBJECTIVE: In anorexia nervosa (AN), medical stabilization and nutritional repletion are pivotal steps toward physical and psychological recovery. Nutritional stabilization is often difficult in this patient group. Recombinant human growth hormone (rhGH) has been safely used as adjuvant therapy in other groups of malnourished patients. We hypothesize that rhGH treatment will hasten medical stabilization in AN patients. STUDY DESIGN: Fifteen patients admitted for inpatient treatment for AN, ages 12-18 years, were enrolled in a 28-day randomized, double-blind, placebo-controlled study. Patients received rhGH (0.05 mg/kg subcutaneously) or an equivalent volume of placebo daily. Outcome measures included time to reach medical/cardiovascular stability, rate of weight gain, and duration of hospitalization. All patients received a standard refeeding protocol. RESULTS: Mean admission body mass index was 14.5 kg/m2. The rhGH and placebo groups did not differ significantly in admission weight, BMI or daily caloric intake. Patients treated with rhGH reached medical/cardiovascular stability more rapidly than those treated with placebo (median 17 vs. 37 days, p = 0.02). Numerical but not statistically significant improvements were seen in weight gain and length of hospitalization in the rhGH group. CONCLUSION: Patients treated with rhGH achieved medical/cardiovascular stability more rapidly than those treated with placebo, and this, in turn, decreased the length of stay.
Assuntos
Anorexia Nervosa/tratamento farmacológico , Hormônio do Crescimento Humano/uso terapêutico , Aumento de Peso , Adolescente , Índice de Massa Corporal , Criança , Método Duplo-Cego , Feminino , Terapia de Reposição Hormonal , Hormônio do Crescimento Humano/farmacologia , Humanos , Tempo de Internação , Masculino , Projetos Piloto , Aumento de Peso/efeitos dos fármacosRESUMO
BACKGROUND: Liver transplantation (LT) remains a high-risk operation, especially during the first months after LT when technical complications and preexisting illness exert their influence on survival. However, there are late deaths. The authors have reviewed their experience to identify factors impacting on long-term survival. METHODS: A total of 150 patients who had undergone liver transplantation over an 11-year period were reviewed. Thirty-three patients died after LT (22%). Of these, 18 of 33 (55%) died in the first 3 postoperative months. One hundred thirty-two patients survived beyond 3 months, and 15 patients (11%) suffered late deaths. This review concentrates on the latter group. RESULTS: The primary cause of death was sepsis in 11 of 15 (73%). In two, sepsis complicated retransplantation in chronically debilitated patients. Two additional patients had late-presenting postoperative complications (bile leak or abscess, intestinal obstruction with perforation). In two cases, pneumocystis carinii pneumonia occurred; noncompliance or unplanned discontinuation of prophylaxis was directly responsible. Multiple organ system failure from presumed immunoincompetence developed in four patients; one had undergone bone marrow transplantation for aplastic anemia (AA) after fulminant hepatic failure (FHF). Lymphoproliferative disease (LPD) was the cause of death in 3 of 15 cases (20%). In only three cases was the cause of death related to the patient's primary disease (chronic hepatitis, Alper's syndrome or seizures, and AA with FHF). Pretransplant diagnosis, and UNOS status at the time of LT did not influence the long-term survival. CONCLUSIONS: Long-term survival in patients who have undergone LT was compromised by immunosuppressive complications and sepsis. Early mortality factors, such as UNOS status, age at LT, primary diagnosis, and technical complications do not predict late deaths. In children who adhere to their medical regimen and have good initial allograft function, late postoperative infection, especially with Ebstein-Barr virus, accounts for most of the late mortality. Improved and decreased immunosuppression may further improve these long-term results.
Assuntos
Atresia Biliar/cirurgia , Transplante de Fígado/mortalidade , Pré-Escolar , Feminino , Encefalopatia Hepática/cirurgia , Humanos , Lactente , Masculino , Complicações Pós-Operatórias , Reoperação , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo , Resultado do Tratamento , Deficiência de alfa 1-Antitripsina/cirurgiaAssuntos
Imunossupressores/uso terapêutico , Falência Hepática/terapia , Transplante de Fígado , Complicações Pós-Operatórias/epidemiologia , Transplante de Células-Tronco/métodos , Criança , Humanos , Falência Hepática/cirurgia , Seleção de Pacientes , Complicações Pós-Operatórias/prevenção & controleRESUMO
Inasmuch as taurine biosynthesis is decreased during early postnatal life, an efficient mechanism for taurine uptake by the liver must be present to maintain intracellular stores of this beta-amino acid. Therefore, basolateral liver plasma vesicles prepared from 14-day and adult rats were used to examine taurine transport during development. For both age groups, the presence of an inwardly directed Na+ gradient stimulated the initial rate of taurine uptake and caused a transient accumulation of taurine above equilibrium. For all time points before equilibrium, taurine uptake was significantly greater with membrane vesicles from 14-day compared to adult rat livers. In contrast, no age-related differences in Na+-independent uptake as measured with a K+ gradient were detected. With equal intravesicular and extravesicular Na+ concentrations, taurine uptake remained significantly greater in the younger age group. For both age groups, Na+-dependent taurine uptake was saturable but the apparent Km and Vmax for Na+-dependent taurine uptake were significantly greater in membrane vesicles from 14-day compared to adult rats. These findings suggest that an increased number of functional carriers for taurine are present in developing compared to adult basolateral plasma membrane perhaps reflecting the needs of the immature liver for this essential nutrient.
Assuntos
Animais Recém-Nascidos/metabolismo , Fígado/metabolismo , Taurina/farmacocinética , Envelhecimento/metabolismo , Animais , Transporte Biológico , Membrana Celular/metabolismo , Feminino , Fígado/citologia , Masculino , Ratos , Ratos Endogâmicos , Sódio/farmacocinéticaRESUMO
Sclerosing cholangitis, an inflammatory disease of the biliary tree that occurs infrequently in childhood, has been recognized in combination with papillary stenosis in adults with the acquired immunodeficiency syndrome. A 10-yr-old child with a familial immunodeficiency syndrome characterized by defective T-cell function and deficiencies of immunoglobulins A and G developed papillary stenosis and sclerosing cholangitis associated with cryptosporidium enteritis. The patient presented with fever, jaundice, right upper quadrant pain, and elevated serum concentrations of transaminases and alkaline phosphatase. The pain and jaundice resolved after endoscopic sphincterotomy, but the biochemical abnormalities persisted. This case demonstrates that the combination of papillary stenosis and sclerosing cholangitis can occur in children as well as adults and may be associated with immunodeficiency syndromes other than the acquired immunodeficiency syndrome. Endoscopic sphincterotomy can provide symptomatic treatment for papillary stenosis in children with this condition, although the effect of sphincterotomy on the natural history of the sclerosing cholangitis is uncertain.