RESUMO
Whereas e-seroconversion represents the loss of hepatitis B e-antigen (HBeAg) followed by gain of antibody to HBeAg (anti-HBe), 'inactive chronic infection' extends this concept to include e-seroconversion with decreased serum viral load and biochemical remission. These events must be well-characterized before treatment outcomes can be evaluated. We examined the rates of e-seroconversion and achievement of inactive chronic infection among children with chronic HBV infection. Children who were HBsAg positive >6 months were identified retrospectively between 1983 and 2008 from the Hospital for Sick Children Liver Clinic. Inactive chronic infection was defined as loss of HBeAg, serum ALT ≤40 IU/mL, and HBV DNA <10(6 ) IU/mL. Both e-seroconversion and achievement of inactive chronic infection were characterized using survival analysis. The effect of transmission route, treatment, age at diagnosis, ethnicity, gender and baseline ALT on these rates was evaluated with univariate and multiple regression. Of 252 HBeAg-positive cases, 59.9% had HBV-infected mothers, 77% were Asian, and 33 received interferon-α. Untreated children were younger at last follow-up (mean 14.5 vs 17.6 years), had lower ALT (median 60 vs 116 IU/mL) and had shorter follow-up (6.6 vs 9.1 years, all P < 0.002) compared to treated children. Crude e-seroconversion rate was 41.7% over 0.5-19.1 years of follow-up, and this was not affected by transmission route (P = 0.93), gender (P = 0.62) nor treatment (P = 0.08). 49% achieved inactive chronic infection by age 19 years. Being non-Asian, age at diagnosis<3 years, and ALT ≥40 IU/mL were associated with a higher rate of e-seroconversion and achieving inactive chronic infection (P < 0.0001). Almost 50% of children achieved inactive chronic infection by early adulthood.
Assuntos
Alanina Transaminase/sangue , DNA Viral/sangue , Antígenos de Superfície da Hepatite B/sangue , Antígenos E da Hepatite B/sangue , Hepatite B Crônica/patologia , Hepatite B Crônica/virologia , Adolescente , Fatores Etários , Antivirais/uso terapêutico , Criança , Etnicidade , Feminino , Humanos , Masculino , Resultado do TratamentoRESUMO
We have previously reported the cloning of a gene that encodes a copper transporting P-type ATPase (ATP7B) which is defective in Wilson disease. We have now identified in 58 WND patients, 20 new mutations as well as three of five previously published mutations: 11 small insertions and deletions, seven missense, two nonsense and three splice site mutations. Two of the mutations are relatively frequent, representing 38% of the mutations in patients of European origin. Our findings suggest a wider spectrum of age of onset than is considered typical of Wilson disease: mutations that completely disrupt the gene can produce liver disease in early childhood when Wilson disease may not typically considered in the differential diagnosis. The mutations identified provide an explanation for at least part of the wide phenotypic variation observed in Wilson disease.
Assuntos
Adenosina Trifosfatases/genética , Proteínas de Transporte de Cátions , Degeneração Hepatolenticular/genética , Idade de Início , Sequência de Aminoácidos , Sequência de Bases , ATPases Transportadoras de Cobre , Primers do DNA/química , Éxons , Feminino , Degeneração Hepatolenticular/epidemiologia , Degeneração Hepatolenticular/etnologia , Heterozigoto , Homozigoto , Humanos , Masculino , Dados de Sequência Molecular , Mutação , Fenótipo , Polimorfismo Conformacional de Fita SimplesRESUMO
Hepatitis in children with haemophilia was historically most often associated with transfusion-transmitted infections. However, with the use of recombinant clotting factor concentrates, acquisition of such infections has now become rare. We studied the profile of hepatitis in North-American children with haemophilia in the modern era of safe blood products and excess childhood obesity. A total of 173 boys (<18 years) registered in the Pediatric Comprehensive Care Haemophilia Program were included in this retrospective study. Hospital records were reviewed for baseline data, serial height and weight measurements and serial alanine aminotransferase (ALT) levels. A body mass index (BMI) ranking was available for 170 boys, of whom 25 (14.7%, 95% CI 9.7-20.9%) were obese. The rate of obesity was higher in severe haemophilic boys. Compared with the general childhood population, the rate of obesity trended towards being higher in young haemophilic boys (2-5 years), but was similar in other age groups. A persistently high ALT (≥80 U L(-1) ) was documented in 5 boys and was associated with obesity. Three boys had clinical and imaging studies compatible with non-alcoholic fatty liver disease (NAFLD). Overweight and obesity are common among haemophilic boys, especially those who are younger and with severe disease. In this large group of haemophilic boys, chronic viral hepatitis was rare and NAFLD was a more common cause of liver disease. Overweight and obese haemophilic boys should be evaluated for NAFLD and interventional programmes should be designed to reduce the potential complications associated with obesity.
Assuntos
Hemofilia A/complicações , Hemofilia B/complicações , Hepatite/epidemiologia , Obesidade/epidemiologia , Adolescente , Fatores Etários , Alanina Transaminase/sangue , Índice de Massa Corporal , Criança , Pré-Escolar , Estudos de Coortes , Fígado Gorduroso/epidemiologia , Hemofilia A/enzimologia , Hemofilia A/fisiopatologia , Hemofilia B/enzimologia , Hemofilia B/fisiopatologia , Hepatite/complicações , Humanos , Masculino , Hepatopatia Gordurosa não Alcoólica , América do Norte/epidemiologia , Obesidade/complicações , Prevalência , Estudos RetrospectivosRESUMO
Conventional kinesin, kinesin-I, is a heterotetramer of two kinesin heavy chain (KHC) subunits (KIF5A, KIF5B, or KIF5C) and two kinesin light chain (KLC) subunits. While KHC contains the motor activity, the role of KLC remains unknown. It has been suggested that KLC is involved in either modulation of KHC activity or in cargo binding. Previously, we characterized KLC genes in mouse (Rahman, A., D.S. Friedman, and L.S. Goldstein. 1998. J. Biol. Chem. 273:15395-15403). Of the two characterized gene products, KLC1 was predominant in neuronal tissues, whereas KLC2 showed a more ubiquitous pattern of expression. To define the in vivo role of KLC, we generated KLC1 gene-targeted mice. Removal of functional KLC1 resulted in significantly smaller mutant mice that also exhibited pronounced motor disabilities. Biochemical analyses demonstrated that KLC1 mutant mice have a pool of KIF5A not associated with any known KLC subunit. Immunofluorescence studies of sensory and motor neuron cell bodies in KLC1 mutants revealed that KIF5A colocalized aberrantly with the peripheral cis-Golgi marker giantin in mutant cells. Striking changes and aberrant colocalization were also observed in the intracellular distribution of KIF5B and beta'-COP, a component of COP1 coatomer. Taken together, these data best support models that suggest that KLC1 is essential for proper KHC activation or targeting.
Assuntos
Cinesinas/metabolismo , Proteínas Associadas aos Microtúbulos/fisiologia , Mutação , Animais , Axônios/metabolismo , Transporte Biológico , Encéfalo/citologia , Encéfalo/metabolismo , Proteína Coatomer , Feminino , Complexo de Golgi/metabolismo , Proteínas da Matriz do Complexo de Golgi , Cinesinas/química , Cinesinas/genética , Masculino , Proteínas de Membrana/análise , Camundongos , Camundongos Endogâmicos , Camundongos Transgênicos , Proteínas Associadas aos Microtúbulos/química , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/metabolismo , Neurônios Motores/citologia , Neurônios Motores/metabolismo , Neurônios Aferentes/citologia , Neurônios Aferentes/metabolismo , Ligação Proteica , Nervo Isquiático/metabolismo , Nervo Isquiático/cirurgiaRESUMO
The effect of PG on patients with fulminant and subfulminant viral hepatitis (FHF) was studied. 17 patients presented with FHF secondary to hepatitis A (n = 3), hepatitis B (n = 6), and non-A, non-B (NANB) hepatitis (n = 8). 14 of the 17 patients had stage III or IV hepatic encephalopathy (HE). At presentation the mean aspartate transaminase (AST) was 1,844 +/- 1,246 U/liter, bilirubin 232 +/- 135 mumol/liter, prothrombin time (PT) 34 +/- 18, partial thromboplastin time (PTT) 73 +/- 26 s, and coagulation Factors V and VII 8 +/- 4 and 9 +/- 5%, respectively. Intravenous PGE1 was initiated 24-48 h later after a rise in AST (2,195 +/- 1,810), bilirubin (341 +/- 148), PT (36 +/- 15), and PTT (75 +/- 18). 12 of 17 responded rapidly with a decrease in AST from 1,540 +/- 833 to 188 +/- 324 U/liter. Improvement in hepatic synthetic function was indicated by a decrease in PT from 27 +/- 7 to 12 +/- 1 s and PTT from 61 +/- 10 to 31 +/- 2 s, and an increase in Factor V from 9 +/- 4 to 69 +/- 18% and Factor VII from 11 +/- 5 to 71 +/- 20%. Five responders with NANB hepatitis relapsed upon discontinuation of therapy, with recurrence of HE and increases in AST and PT, and improvement was observed upon retreatment. After 4 wk of intravenous therapy oral PGE2 was substituted. Two patients with NANB hepatitis recovered completely and remained in remission 6 and 12 mo after cessation of therapy. Two additional patients continued in remission after 2 and 6 mo of PGE2. No relapses were seen in the patients with hepatitis A virus and hepatitis B virus infection. Liver biopsies in all 12 surviving patients returned to normal. In the five nonresponders an improvement in hepatic function was indicated by a fall in AST (3,767 +/- 2,611 to 2,142 +/- 2,040 U/liter), PT (52 +/- 25 to 33 +/- 18 s), and PTT (103 +/- 29 to 77 +/- 44 s), but all deteriorated and died of cerebral edema (n = 3) or underwent liver transplantation (n = 2). These results suggest efficacy of PGE for FHF, and further investigation is warranted.
Assuntos
Alprostadil/uso terapêutico , Hepatite Viral Humana/tratamento farmacológico , Adolescente , Adulto , Aspartato Aminotransferases/sangue , Bilirrubina/sangue , Coagulação Sanguínea/efeitos dos fármacos , Criança , Dinoprostona/uso terapêutico , Feminino , Hepatite Viral Humana/sangue , Humanos , Fígado/efeitos dos fármacos , Fígado/patologia , Fígado/fisiopatologia , Masculino , Pessoa de Meia-IdadeRESUMO
Proteins of the kinesin superfamily define a class of microtubule-dependent motors that play crucial roles in cell division and intracellular transport. In the mouse, several kinesin motors have been characterized and are suggested to play roles in axonal and/or dendritic transport. One such kinesin is KifC2. Sequence and secondary structure analysis revealed that KifC2 is a member of the C-terminal motor family. Northern and Western blot analyses indicated that KifC2 is specifically expressed in both the central and peripheral nervous systems. The cellular locations of the KifC2 proteins were found to be mainly in neural cell bodies and dendrites but also in axons. To understand the in vivo function of the KifC2 gene, we used homologous recombination in embryonic stem cells to construct knockout mouse strains for the KifC2 gene. Homozygous KifC2 mutants were viable and reproduced normally, and their development was apparently normal. These results suggest that KifC2 is dispensable for normal neural development and behavior in the mouse.
Assuntos
Cinesinas/genética , Proteínas do Tecido Nervoso/genética , Animais , Cinesinas/metabolismo , Camundongos , Camundongos Knockout , Proteínas Motores Moleculares/genética , Proteínas Motores Moleculares/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Recombinação GenéticaRESUMO
Members of the kinesin II family are thought to play essential roles in many types of intracellular transport. One distinguishing feature of kinesin II is that it generally contains two different motor subunits from the Kif3 family. Three Kif3 family members (Kif3A, Kif3B, and Kif3C) have been identified and characterized in mice. Intracellular localization and biochemical studies previously suggested that Kif3C is an anterograde motor involved in anterograde axonal transport. To understand the in vivo function of the Kif3C gene, we used homologous recombination in embryonic stem cells to construct two different knockout mouse strains for the Kif3C gene. Both homozygous Kif3C mutants are viable, reproduce normally, and apparently develop normally. These results suggest that Kif3C is dispensable for normal neural development and behavior in the mouse.
Assuntos
Regulação da Expressão Gênica , Cinesinas/análise , Animais , Deleção de Genes , Cinesinas/genética , Cinesinas/metabolismo , Camundongos , Camundongos KnockoutRESUMO
Proteins of the kinesin superfamily define a class of microtubule-dependent motors that play crucial roles in cell division and intracellular transport. To study the molecular mechanism of intracellular transport involving microtubule-dependent motors, a cDNA encoding a new kinesin-like protein called KifC3 was cloned from a mouse brain cDNA library. Sequence and secondary structure analysis revealed that KifC3 is a member of the C-terminal motor family. In contrast to other mouse C-terminal motors, KifC3 is apparently ubiquitous and may have a general role in intracellular transport. To understand the in vivo function of the KifC3 gene, we used homologous recombination in embryonic stem cells to construct knockout mouse strains for the KifC3 gene. Homozygous mutants of the KifC3 gene are viable, reproduce normally, and apparently develop normally. These results suggest that KifC3 is dispensable for normal development and reproduction in the mouse.
Assuntos
Cinesinas/genética , Cinesinas/fisiologia , Proteínas Motores Moleculares/genética , Proteínas Motores Moleculares/fisiologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , DNA Complementar/genética , Feminino , Expressão Gênica , Crescimento/genética , Crescimento/fisiologia , Rim/anatomia & histologia , Rim/metabolismo , Cinesinas/química , Masculino , Camundongos , Camundongos Knockout , Proteínas Motores Moleculares/química , Dados de Sequência Molecular , Fenótipo , Gravidez , Reprodução/genética , Reprodução/fisiologia , Retina/metabolismoRESUMO
In laboratory animals and in mouse hepatoma cells in culture the Ah receptor previously has been shown to mediate induction of aryl hydrocarbon hydroxylase (cytochrome P1-450) by 3-methylcholanthrene, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. We examined human lung cytosols to determine whether the Ah receptor was present in human tissues. Cytosol was prepared from grossly normal lung tissue obtained at pulmonary lobectomy for presumed lung cancer from 53 consecutive adult patients including 32 males (42-77 years old) and 21 females (18-81 years old). Ah receptor in the cytosols was identified and quantitated by specific binding of [3H]TCDD after separation by ultracentrifugation on sucrose gradients. Specific binding of [3H]TCDD to a component which met the criteria for Ah receptor was detected in 10 of the 53 specimens. As previously established in tissues from laboratory animals, the specific [3H]TCDD-binding component sedimented approximately 9S. Binding of [3H]TCDD to the 9S component was competitively inhibited by incubation in the presence of 2,3,7,8-tetrachlorodibenzofuran, dibenz(a,h)anthracene, and nonradioactive TCDD, all known to be potent agonists for Ah-receptor-mediated induction of aryl hydrocarbon hydroxylase. Specific Ah receptor also was detected in some specimens by direct binding of [3H]-3-methylcholanthrene. The human population studied exhibited striking heterogeneity in Ah receptor concentrations. Only 10 of the 53 individuals studied had detectable Ah receptor. In specimens with detectable specific binding, the mean concentration of binding sites was 6.9 +/- 1.2 (SE) fmol/mg cytosolic protein. These concentrations are approximately 10-30% of the concentrations of Ah receptor found in lung cytosols from laboratory animals. Our experiments indicate that the Ah receptor can be detected in lung cytosol from some humans and suggest that the regulatory mechanism mediating human cytochrome P1-450 induction may be similar to that in the murine model. Aryl hydrocarbon hydroxylase, the major enzyme induced under control of the Ah receptor, plays an important role in the metabolism of several carcinogens including polycyclic aromatic hydrocarbons such as benzo(a)pyrene. It is possible that differences in the Ah receptor content within the human population may be genetically based and that variation at the Ah receptor level may be an important determinant of individual susceptibility to certain chemically induced cancers.
Assuntos
Hidrocarboneto de Aril Hidroxilases/biossíntese , Dioxinas/metabolismo , Pulmão/metabolismo , Dibenzodioxinas Policloradas/metabolismo , Receptores de Droga/metabolismo , Citosol/metabolismo , Indução Enzimática , Humanos , Ensaio Radioligante , Receptores de Hidrocarboneto ArílicoRESUMO
Aryl hydrocarbon hydroxylase (AHH, cytochrome P1-450) is highly inducible in several human cells and tissues exposed to specific halogenated and nonhalogenated aromatic chemicals of the "3-methylcholanthrene-type." In laboratory animals AHH induction is known to be regulated by binding of inducers to the Ah receptor, a soluble intracellular protein. However, the induction mechanism in the human species is incompletely understood largely because the Ah receptor, which seems to be essential to the induction process, has not previously been detectable in certain human cells and tissues (including placenta) that are highly responsive to AHH induction. We found that human placenta contains high concentrations of Ah receptor (comparable to the receptor concentrations in rat and mouse liver) but that special modifications were necessary in the assay techniques in order to detect and accurately quantitate receptor binding. Receptor was detected at concentrations approximately equal to 100 fmol/mg cytosol protein using [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as the radioligand. This high concentration of specific binding sites was present only if the placental tissue was initially homogenized in a buffer containing sodium molybdate (10 or 20 mM). Without molybdate in the homogenizing buffer, specific [3H]TCDD binding was only about 35 fmol/mg. Specific Ah receptor binding also was detectable with [3H]-3-methylcholanthrene and, to a lesser extent, with [3H]-benzo(alpha)pyrene. The receptor sedimented near 9S on sucrose gradients whether molybdate was present or not. About 80% of specific binding was lost if excessive charcoal was used to adsorb "nonspecifically bound" ligand from cytosol prior to gradient analyses. The apparent affinity with which [3H]TCDD bound to Ah receptor in human placental cytosol was relatively low (apparent Kd approximately equal to 5 to 8 nM) when compared with the affinity of [3H]TCDD binding in rat or mouse hepatic cytosols (Kd approximately equal to 1 to 3 nM). These data suggest that while molybdate has very little effect on the quantity or molecular size of the rodent Ah receptor assay, it is very important in stabilizing the human Ah receptor. Our experiments demonstrate that human placenta contains a high concentration of Ah receptor and suggest that AHH induction in placenta is mediated through a receptor mechanism analogous to that previously established in tissues and cells from laboratory animals.
Assuntos
Benzo(a)pireno/metabolismo , Dioxinas/metabolismo , Metilcolantreno/metabolismo , Molibdênio/farmacologia , Placenta/análise , Dibenzodioxinas Policloradas/metabolismo , Receptores de Droga/análise , Centrifugação com Gradiente de Concentração , Carvão Vegetal/farmacologia , Citosol/metabolismo , Feminino , Humanos , Técnicas In Vitro , Placenta/metabolismo , Gravidez , Ensaio Radioligante , Receptores de Hidrocarboneto Arílico , Preservação de TecidoRESUMO
A close examiniation of several indices of contractility derived from the ventricular pressure was made using an isolated canine heart preparation. The repsonses to single intracoronary injections of calcium chloride as well as to increasing doses of this agent were tested. From the latter, calcium dose-transient-response curves intended to reveal the extent of myocardial/contractile reserve were constructed. Indices included various extrapolations to maximal velocity of shortening at zero load, maximal value of the quotient of the first derivative and ventricular pressure, time-tension index, energy averaged power density, and power averaged rate of generation of power density. Indices were compared over the same cardiac cycles before and after administration of calcium. Most indices showed increments from 10 to 20%, except power density functions which had increments of 40 and 70%, respectively. Calcium dose-response curves were linear for most indices, but, again, the power density functions showed the steepest slopes. After severe coronary occlusion, the curves for most indices flattened and lost linearity and, presumably, this was due to loss of myocardial contractile reserve. For milder occlusions, only the power density functions showed significant flattening. The conceptual framework of a contractile myocardial reserve appears supported by these results.
Assuntos
Fenômenos Biomecânicos , Contração Miocárdica , Animais , Cloreto de Cálcio/farmacologia , Doença das Coronárias/fisiopatologia , Cães , Relação Dose-Resposta a Droga , Contração Miocárdica/efeitos dos fármacosRESUMO
UNLABELLED: To evaluate the diagnostic information gained from hepatobiliary scanning in infants, we reviewed 86 consecutive infants who were < or = 4 mo old and were treated for conjugated hyperbilirubinemia at the Hospital for Sick Children in Toronto between 1985 and 1993 and who had technetium iminodiacetic hepatobiliary scanning and a percutaneous liver biopsy performed in close temporal proximity. METHODS: Retrospective reviews of hospital charts and blinded reviews of hepatobiliary scans were performed. RESULTS: There were 58 male and 28 female infants (age range, 2-124 days; mean = 65 days). Hepatobiliary scanning failed to show biliary excretion into the gastrointestinal tract in 53 of 86 patients. Forty of these 53 had extrahepatic biliary atresia. The remaining 33 patients demonstrated biliary excretion into the gastrointestinal tract; 24 of 33 had neonatal hepatitis. Among 13 of the 53 patients who had no evidence of biliary excretion and who also did not have extrahepatic biliary atresia, 8 had idiopathic neonatal hepatitis, 4 had interlobular bile duct paucity and 1 had total parenteral nutrition-associated cholestasis. In this large series, no patient with extrahepatic biliary atresia showed bile drainage on hepatobiliary scanning. Fifty percent of patients with interlobular bile duct paucity but no extrahepatic obstruction failed to show biliary excretion of radionuclide. Twenty-five percent of patients (8 of 32) with idiopathic neonatal hepatitis demonstrated no biliary excretion. Hepatocellular extraction was examined by semiquantitative analysis in the nondraining, nonbiliary atresia patients (12 of 53). Four of these 12 patients demonstrated poor liver extraction. Three patients had idiopathic neonatal hepatitis, and one had bile duct paucity. Therefore, four of eight neonatal hepatitis patients had normal extraction, suggesting that poor versus good liver hepatocyte clearance cannot accurately identify neonatal hepatitis. CONCLUSION: Hepatobiliary scanning requires cautious interpretation. Nondraining scans may indicate severe neonatal hepatitis or the presence of interlobular bile duct paucity.
Assuntos
Síndrome de Alagille/diagnóstico por imagem , Atresia Biliar/diagnóstico por imagem , Sistema Biliar/diagnóstico por imagem , Hepatite/diagnóstico por imagem , Icterícia Neonatal/diagnóstico por imagem , Fígado/diagnóstico por imagem , Síndrome de Alagille/complicações , Atresia Biliar/complicações , Biópsia , Feminino , Hepatite/complicações , Humanos , Iminoácidos , Lactente , Recém-Nascido , Icterícia Neonatal/etiologia , Fígado/patologia , Masculino , Compostos de Organotecnécio , Cintilografia , Estudos Retrospectivos , Disofenina Tecnécio Tc 99mRESUMO
The shedding of rod outer segment disc membrane was investigated in a commonly used frog eyecup preparation, with respect to length of time in vitro. It was found that the amplitude, but not the timing, of the "dawn" (ie, when the lights are turned on) shedding response was increased threefold if the time in vitro was increased from 1.5-2 hr to 12-13 hr before dawn. After the overnight incubation, morphologic deterioration of the photoreceptors was not apparent by light or electron microscopy. The addition of the antioxidants, vitamin C or alpha-tocopherol (vitamin E), inhibited the increase in shedding, suggesting that it was induced by oxidation. These results help define conditions necessary for the maintenance of normal retinal metabolism in vitro. They also suggest a link between the amplitude of the dawn disc membrane shedding response and oxidation.
Assuntos
Ácido Ascórbico/farmacologia , Células Fotorreceptoras/fisiologia , Vitamina E/farmacologia , Animais , Membrana Celular/fisiologia , Oxirredução , Células Fotorreceptoras/ultraestrutura , Segmento Externo da Célula Bastonete/fisiologia , Segmento Externo da Célula Bastonete/ultraestrutura , Xenopus laevisRESUMO
Transient transfection and in vitro infection experiments were performed to characterize replication and antigen synthesis of the hepatitis B virus (HBV) in human hepatocyte lines HH29 and HHY41, derived from normal liver tissue. These liver cell lines are capable of supporting HBV replication and gene expression at levels similar to the human hepatoma cell line HuH-7. Strikingly, a very tight adhesion of HBV to the outer cell membrane of HH29 and HHY41 was observed under conditions that removed HBV to undetectable levels from HuH-7 hepatoma cells. However, no productive HBV infection could be established in these cells as determined by the absence of viral transcripts and de novo antigen synthesis. In conclusion, the human hepatocyte cell lines HH29 and HHY41 may be useful to study important aspects of late steps in the replication of HBV, but appear to lack certain cellular components that play a pivotal role during early steps of the viral life cycle.
Assuntos
Replicação do DNA , Antígenos de Superfície da Hepatite B/biossíntese , Antígenos E da Hepatite B/biossíntese , Vírus da Hepatite B/fisiologia , Replicação Viral , Linhagem Celular , DNA Viral/biossíntese , Vírus da Hepatite B/genética , Vírus da Hepatite B/imunologia , Humanos , Fígado/citologia , Células Tumorais CultivadasRESUMO
The Ah receptor regulates induction of cytochrome P450IA1 and mediates certain toxicities of polyhalogenated aromatics such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). It has been characterized previously in continuous cell lines, notably the mouse hepatoma line Hepa 1, the human squamous cell carcinoma line A431, and the human liver cell line Hep G2. The present work extends our knowledge of the Ah receptor in continuous human liver cell lines. Ah receptor can be detected in Mz-Hep-1, a hepatitis B virus-negative cell line derived from a Thorotrast-induced hepatocellular carcinoma. The mean concentration of Ah receptor in Mz-Hep-1 cells was 341 +/- 22 fmol/mg cytosol protein (mean +/- SEM, nine separate determinations). This is equivalent to approximately 30,000 sites per cell. The concentration of Ah receptor in Mz-Hep-1 cells is similar to that in Hepa 1 cells and approximately three times higher than that in Hep G2 cells. The Mz-Hep-1 Ah receptor sedimented in continuous sucrose gradients at approximately 9 S. Specificity of binding by [3H]TCDD was demonstrated by competitive binding of non-radiolabeled 2,3,7,8-tetrachlorodibenzofuran, 3-methylcholanthrene (MC), and dibenz[a,h]anthracene in 50-fold molar excess. Phenobarbital, which is not a substrate for P450IA1, did not compete with [3H]TCDD for binding to Mz-Hep-1 Ah receptor. Dexamethasone and estradiol also did not compete with [3H]TCDD for binding, suggesting non-identity of Ah receptor with glucocorticoid or estrogen receptor. In separate experiments, glucocorticoid receptor was identified in Mz-Hep-1 cells. By Scatchard plot analysis, the apparent equilibrium dissociation constant (Kd) for binding of [3H]TCDD to Mz-Hep-1 Ah receptor was estimated to be 4.4 nM, compared to 0.8 nM in Hepa 1 cells. By Woolf plot analysis the Kd was 5.4 nM, compared to 1.2 nM in Hepa 1 cells. The [3H]TCDD.Ah receptor complex extracted from nuclei of Mz-Hep-1 cells incubated with [3H]TCDD in culture at 37 degrees sedimented at approximately 6 S under conditions of high ionic strength. Aryl hydrocarbon hydroxylase (AHH) activity was detectable in Mz-Hep-1 cells after pretreatment with inducing chemicals. Mz-Hep-1 cells have the highest concentrations of Ah receptor in any continuous human liver cell line thus far investigated. The Mz-Hep-1 Ah receptor is similar physicochemically to that described in murine systems. AHH activity is inducible in Mz-Hep-1 cells.
Assuntos
Hidrocarboneto de Aril Hidroxilases/biossíntese , Carcinoma Hepatocelular/metabolismo , Sistema Enzimático do Citocromo P-450/biossíntese , Neoplasias Hepáticas/metabolismo , Dibenzodioxinas Policloradas/farmacologia , Receptores de Droga/metabolismo , Animais , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Centrifugação com Gradiente de Concentração , Citosol/efeitos dos fármacos , Citosol/metabolismo , Indução Enzimática , Humanos , Camundongos , Receptores de Hidrocarboneto Arílico , Receptores de Droga/efeitos dos fármacos , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismoRESUMO
Ethoxyresorufin O-deethylation (EROD) has been used as a specific probe for CYP1A1 and CYP1A2. Selective inhibition of one of these cytochromes P450 may differentiate their activity in human liver. Four inhibitors were chosen to examine the selective inhibition of EROD activity, using cDNA of CYP1A1 and CYP1A2. The two flavones, alpha-naphthoflavone and apigenin, while differing in potency, inhibited expressed human CYP1A1, CYP1A2, and human liver microsomes to a similar extent. Isosafrole and fluvoxamine were found to inhibit CYP1A2 selectively, with Ki values of 14 and 800 times, respectively, lower than those for CY1A1. A set of equations was developed to estimate both CYP1A1 and CYP1A2 activity. Levels of CYP1A2 in four human liver specimens ranged from 44.4 to 76.7 pmol/mg protein, which significantly correlated with phenacetin O-deethylase activity (r = 0.99; P < 0.001). Low levels of CYP1A1 activity were present in all four investigated livers, ranging from 0.4 to 2.7 pmol/mg protein.
Assuntos
Citocromo P-450 CYP1A1/antagonistas & inibidores , Inibidores do Citocromo P-450 CYP1A2 , Inibidores Enzimáticos/farmacologia , Fluvoxamina/farmacologia , Safrol/farmacologia , Linhagem Celular , Humanos , Fígado/enzimologiaRESUMO
Joubert syndrome is an autosomal recessive inherited condition characterized by agenesis or hypoplasia of the cerebellar vermis, retinal dystrophy, chorioretinal colobomata, oculomotor abnormalities, episodic hyperpnea, ataxia, and mental retardation. Congenital hepatic fibrosis has not previously been described in Joubert syndrome. We report two unrelated children with Joubert syndrome and hepatosplenomegaly. On histopathological examination, both had congenital hepatic fibrosis. Both were also found to have congenital medullary cystic disease of the kidneys. Joubert syndrome appears to be one of a spectrum of congenital malformation syndromes involving the central nervous system, eye, liver and kidneys.
Assuntos
Anormalidades Múltiplas , Cerebelo/anormalidades , Anormalidades do Olho/patologia , Rim/anormalidades , Cirrose Hepática/congênito , Anormalidades Múltiplas/patologia , Pré-Escolar , Deficiências do Desenvolvimento , Feminino , Humanos , Lactente , Cirrose Hepática/patologia , Masculino , SíndromeRESUMO
Since 1970 all patients admitted with penetrating injuries near the cardiac silhouette are transferred immediately to the operating room for resuscitation and evaluation for immediate thoracotomy. The clinical courses of 10 patients with penetrating cardiac injuries treated between 1962 and 1969 were analyzed and compared with those of 33 patients who presented between 1970 and 1977 and were managed more aggressively. Since the institution of this more aggressive policy, overall survival has improved from 20% to 67%. In patients arriving in the emergency room with signs of viability, survival increased from 29% to 76%. Of 53 patients with injuries in the area of the cardiac silhouette, 33 (62%) actually sustained cardiac injury. The high probability of cardiac injury in patients with external wounds in the silhouette and the improved survival rate seen with aggressive surgical therapy justifies the change to this policy.
Assuntos
Traumatismos Cardíacos/cirurgia , Ferimentos Penetrantes/cirurgia , Adolescente , Adulto , Traumatismos Cardíacos/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Fatores de TempoRESUMO
We describe a 14-year-old bone marrow transplant recipient who was anti-HBs-positive before the procedure and afterwards developed acute infection with hepatitis B virus (HBV). Liver biopsies taken while symptomatic showed portal fibrosis progressing to cirrhosis. The patient responded to lamivudine treatment with HBeAg seroconversion and significant regression of fibrosis. Although the source and timing of HBV exposure remain unclear, the potential for severe hepatitis B infection following bone marrow transplant warrants caution. This case demonstrates that a symptomatic HBV infection can occur in an immunocompromised patient who had originally been anti-HBs-positive.
Assuntos
Transplante de Medula Óssea/efeitos adversos , Hepatite B/tratamento farmacológico , Lamivudina/administração & dosagem , Adolescente , Anticorpos Antivirais/sangue , Feminino , Hepatite B/etiologia , Antígenos de Superfície da Hepatite B/imunologia , Humanos , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/terapia , Cirrose Hepática/etiologia , Cirrose Hepática/virologia , Ativação ViralRESUMO
Liver biopsies from 155 patients with alcoholic liver disease were examined for periodic-acid-Schiff-positive, diastase-resistant (PAS-DR) intracytoplasmic globules in hepatocytes. Seven patients had these PAS-DR globules: each was a heterozygote for a deficiency allele of alpha-1-antitrypsin (AAT), or alpha-1-protease inhibitor, with the PAS-DR globules distributed in a pattern characteristic of this deficiency. One further patient with normal AAT had a few intracytoplasmic PAS-DR globules in occasional hepatocytes. The prevalence of AAT heterozygotes in this series did not differ from that in the reference population. The seven heterozygotes included five of PI (protease inhibitor) type MZ, one of PI type SZ, and one heterozygous for a rare deficiency allele, PI type MMmalton. The M and Mmalton alleles may be difficult to distinguish because they have similar mobilities with isoelectric focusing technics. Therefore, if PAS-DR inclusions are found in the liver of a patient with an apparently normal phenotype, the presence of a defective M variant allele, such as Mmalton, should be considered.