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Biomedical subjects

Michael R Narkewicz

Publications and source records attributed to Michael R Narkewicz.

At least 19 recordsLinked to original sources
PubMed2006

Acute liver failure in children: the first 348 patients in the pediatric acute liver failure study group.

OBJECTIVES: To determine short-term outcome for children with acute liver failure (ALF) as it relates to cause, clinical status, and patient demographics and to determine prognostic factors. STUDY DESIGN: A prospective, multicenter case study collecting demographic, clinical, laboratory, and short-term outcome data on children from birth to 18 years with ALF. Patients without encephalopathy were included if the prothrombin time and international normalized ratio remained > or = 20 seconds and/or >2, respectively, despite vitamin K. Primary outcome measures 3 weeks after study entry were death, death after transplantation, alive with native liver, and alive with transplanted organ. RESULTS: The cause of ALF in 348 children included acute acetaminophen toxicity (14%), metabolic disease (10%), autoimmune liver disease (6%), non-acetaminophen drug-related hepatotoxicity (5%), infections (6%), other diagnosed conditions (10%); 49% were indeterminate. Outcome varied between patient sub-groups; 20% with non-acetaminophen ALF died or underwent liver transplantation and never had clinical encephalopathy. CONCLUSIONS: Causes of ALF in children differ from in adults. Clinical encephalopathy may not be present in children. The high percentage of indeterminate cases provides an opportunity for investigation.

Adolescent↗
PubMed2006

Safety, efficacy and pharmacokinetics of peginterferon alpha2a (40 kd) in children with chronic hepatitis C.

Chronic hepatitis C virus (HCV) infection in children is a problem affecting thousands of children worldwide. Although standard interferon (INF) has better efficacy in pediatric patients than in adults, results in children with genotype 1 are poor; response rates to combination treatment with standard INF and ribavirin are better but the treatment requires thrice-weekly injections. The improved antiviral efficacy of weekly pegylated interferons relative to standard interferons in adults with chronic HCV infection suggests that pegylated interferons may also improve antiviral efficacy in children. We therefore investigated the pharmacokinetics, efficacy and safety of peginterferon alpha2a (pegINF-alpha2a) (40 kd) in 14 children ages 2 to 8 years with chronic hepatitis C (13 genotype 1, 1 non-1 genotype). Drug dose was calculated from each patient's body surface area (BSA) according to the formula BSA (m2)/(1.73 m2) x 180 microg, and patients were administered once-weekly subcutaneous injections for 48 weeks. Viral load and pharmacokinetic parameters were determined from blood drawn throughout the study and during follow-up. At week 24, the mean trough concentration was about 20% below values obtained from adults treated with pegINF-alpha2a, and the area under the curve from 0 to 168 hours was about 20% above adult values, suggesting that drug doses calculated from BSA achieved therapeutically adequate concentrations. Six of 14 patients (43%), all infected with genotype 1, achieved a sustained virological response. Adverse events were those commonly associated with INF-based treatment, and none was deemed serious. In conclusion, our findings provide a basis for larger studies evaluating the efficacy and safety of pegINF-alpha2a as monotherapy as well as in combination with ribavirin in pediatric patients with chronic hepatitis C.

Antiviral Agents↗
PubMed2005

Characterization of acute liver failure and development of a continuous risk of death staging system in children.

BACKGROUND/AIMS: Acute liver failure (ALF) in children has been associated with an overall mortality of approximately 70% in the pretransplant era and 50-80% survival in those undergoing orthotopic liver transplantation. There is currently no system for staging severity of ALF in children. The aim of this study was to characterize pediatric ALF in a tertiary hospital and to derive a scoring system to stratify severity of ALF based on predicted mortality. METHODS: Prospective data collection of 81 children from December 1993-2003 who presented with ALF. Data recorded included peak laboratory values, clinical characteristics, and survival. RESULTS: Transplant-free survival was 56% with overall survival including those undergoing OLT of 72%. Transplantation rate was 22% with transplant survival of 72%. Of the peak laboratory values analyzed, total bilirubin, prothrombin time/INR, and ammonia were the most predictive of death or a need for liver transplant. A simple risk staging system was developed based on the ability of these three laboratory measurements to predict mortality. CONCLUSIONS: The survival in pediatric ALF has improved in recent years. Risk staging for ALF could potentially be used in clinical research for risk-adjusted outcomes analysis and to help stratify patients for clinical studies according to mortality risk.

Ammonia↗
PubMed2005

Comparison of indices of vitamin A status in children with chronic liver disease.

Malabsorption of fat-soluble vitamins is a major complication of chronic cholestatic liver disease. The most accurate way to assess vitamin A status in children who have cholestasis is unknown. The goal of this study was to assess the accuracy of noninvasive tests to detect vitamin A deficiency. Children with chronic cholestatic liver disease (n = 23) and noncholestatic liver disease (n = 10) were studied. Ten cholestatic patients were identified as vitamin A-deficient based on the relative dose response (RDR). Compared with the RDR, the sensitivity and specificity to detect vitamin A deficiency for each test was, respectively: serum retinol, 90% and 78%; retinol-binding protein (RBP), 40% and 91%; retinol/RBP molar ratio, 60% and 74%; conjunctival impression cytology, 44% and 48%; slit-lamp examination, 20% and 66%; tear film break-up time, 40% and 69%; and Schirmer's test, 20% and 78%. We developed a modified oral RDR via oral coadministration of d-alpha tocopheryl polyethylene glycol-1000 succinate and retinyl palmitate. This test had a sensitivity of 80% and a specificity of 100% to detect vitamin A deficiency. In conclusion, vitamin A deficiency is relatively common in children who have chronic cholestatic liver disease. Our data suggest that serum retinol level as an initial screen followed by confirmation with a modified oral RDR test is the most effective means of identifying vitamin A deficiency in these subjects.

Administration, Oral↗
PubMed2005

Portopulmonary hypertension in pediatric patients.

OBJECTIVES: To investigate the clinical presentation, manifestations, and response to therapy of portopulmonary hypertension (PPHTN) in pediatric patients. STUDY DESIGN: This study was a retrospective chart review describing the evaluation and course of 7 patients with PPHTN. RESULTS: Causes of portal hypertension (HTN) included biliary atresia (3 cases), cavernous transformation of the portal vein (2 cases), and primary sclerosing cholangitis and cryptogenic cirrhosis (1 case each). The median interval from the diagnosis of portal HTN to PPHTN was 12.1 years. Four patients presented with a new heart murmur, 4 presented with syncope, and 3 presented with dyspnea. Although electrocardiograms (ECGs) and chest x-rays were normal in 3 and 2 patients, respectively, echocardiograms diagnosed pulmonary HTN in all 7 patients. Five patients had cardiac catheterizations; the average mean pulmonary artery pressure was 65 +/- 20 mm Hg. Response to therapy was variable, and 4 patients died. Postmortem lung tissue examination revealed plexiform lesions and pulmonary arteriopathy. CONCLUSIONS: Because symptoms are subtle and may be overlooked, pediatric patients with portal HTN who develop a new heart murmur, dyspnea, syncope, or who are being evaluated for liver transplantation require evaluation for PPHTN. ECG and chest x-ray are insensitive screens for PPHTN. An echocardiogram and cardiology evaluation is essential for the diagnosis.

Adolescent↗
PubMed2005

Connective tissue growth factor expression is increased in biliary epithelial cells in biliary atresia.

BACKGROUND/PURPOSE: Connective tissue growth factor (CTGF) has been implicated in the pathogenesis of hepatic fibrosis and is elevated in the serum of children with biliary atresia (BA). The objective of this study was to evaluate hepatic CTGF messenger RNA (mRNA) expression and its relationship to hepatic histology in children with BA. METHODS: Connective tissue growth factor mRNA expression was evaluated by in situ hybridization in 26 liver biopsies from 11 patients with BA, 11 with other diseases, and 4 autopsy controls. Serial sections were immunostained with cell-specific markers to characterize the cells expressing CTGF. Biopsies were scored for CTGF expression (0-4) and inflammation and fibrosis (1-4). RESULTS: High levels of CTGF expression were observed in 9 of 11 BA with localization to biliary epithelial cells and vascular endothelial cells. Connective tissue growth factor mRNA expression was correlated with fibrosis in BA and all livers. In the 11 patients with other liver diseases, 7 had CTGF expression limited to hepatic stellate cells and vascular endothelial cells. None of the 4 livers in children without liver disease had significant levels of CTGF. CONCLUSIONS: In BA livers, novel biliary epithelia CTGF mRNA expression is high and correlates with severity of fibrosis. These data support a role for biliary epithelial cell signaling in fibrogenesis.

Adolescent↗
PubMed2004

Interferon treatment for chronic hepatitis B: enhanced response in children 5 years old or younger.

OBJECTIVE: To test the hypothesis that there is an improved response to interferon in children with chronic hepatitis B (HBV) who are < or =5 years of age. STUDY DESIGN: Retrospective chart review of 22 consecutive children with chronic HBV (ages 17 months to 17 years; median, 83.9 months; 14 male, 8 female) treated with interferon-alpha2b. RESULTS: Ten patients (48%) responded to treatment [HBeAg (-), Anti-HBe (+), HBV DNA (-), HBsAg (+) and normal alanine aminotransferase/aspartate aminotransferase (ALT/AST) at 6 months after treatment], and 5 seroconverted HBsAg [above plus HBsAg negative and anti-HBs (+)]. Seven of 9 patients (78%) < or =5 years of age responded (5 cleared HBsAg). Three of 13 patients (23%) >5 years of age responded. Patient age at treatment was significantly lower in responders (63 +/- 70 months) versus nonresponders (104 +/- 55 months, P =.005). AST, ALT, and HBV DNA at the start of treatment were not different between responders and nonresponders or between patients < or =5 and >5 years old. CONCLUSIONS: Interferon treatment may be more effective in younger children with chronic hepatitis B.

Adolescent↗
PubMed2003

Hepatic dysfunction following the Fontan procedure.

OBJECTIVES: The Fontan procedure offers a palliation for the hemodynamic derangements associated with congenital heart lesions characterized by a single functional ventricle, but it causes a chronically elevated systemic venous pressure that may result in hepatic congestion. The objective of this study was to characterize hepatic function and its relationship to cardiac function in children who had undergone the Fontan procedure. METHODS: In a cross-sectional study of 11 children aged 38 months to 216 months (mean, 149 months), the authors evaluated indices of cardiac and hepatic function, including galactose clearance, Doppler hepatic ultrasonography, synthetic function, and markers of liver injury, at 9 months to 176 months (mean, 100 months) after children had undergone the Fontan procedure. RESULTS: The most common biochemical abnormality of hepatic function was a prolongation of the prothrombin time and a low factor V level. There was a trend toward progressive abnormality in prothrombin time with increasing interval since the Fontan procedure. Galactose elimination half-life and galactose elimination capacity were inversely correlated with the time after Fontan (R2= 0.65, P = 0.004). There was no relationship between cardiac functional measurements and liver function. CONCLUSIONS: Prothrombin time and galactose elimination half-life are abnormal in children who have undergone the Fontan procedure and may be useful markers of hepatic function in the longitudinal assessment of these patients.

Adolescent↗
PubMed2003

Plasma markers of platelet activation in cystic fibrosis liver and lung disease.

BACKGROUND: Transforming growth factor beta 1 (TGFbeta1) is a major fibrogenic cytokine, the expression of which is increased in the livers of children with cystic fibrosis liver disease (CFLD) and in the bronchoalveolar lavage fluid of patients with cystic fibrosis pulmonary disease (CFPD). The purpose of our study was to investigate the usefulness of plasma TGFbeta1 as a noninvasive marker of CFLD and CFPD, or both and to investigate the contribution of platelet-derived TGFbeta1 to plasma TGFbeta1 by correlating the latter with platelet factor 4 (PF4). METHODS: Three groups of patients with cystic fibrosis were studied: 1) those with CFLD, 2) those with CF and no liver disease (CFNLD), and 3) those with CFPD. Controls were healthy adolescents and adults. Plasma TGFbeta1 was assayed using the R and D Quantikine quantitative sandwich enzyme immunoassay technique and PF4 (American Bioproducts ELISA kit). RESULTS: Plasma TGFbeta1 was markedly increased in CFPD (15 +/- 3 ng/mL) versus healthy adults (1 +/- 0 ng/mL; P < 0.004. The PF4 values followed a similar pattern: 105 +/- 8 ng/mL in CFPD versus 12 +/- 4 ng/mL (P < 0.0001). Plasma TGFbeta1 values in CFLD did not differ from CFNLD patients of comparable age nor from values for healthy adolescents. Plasma TGFbeta1 values were strongly correlated with values for PF4: r = 0.543, P < 0.0001. CONCLUSIONS: Plasma TGFbeta1 is not a useful marker of CFLD. The increased plasma TGFbeta1 and PF4 in CFPD patients are of interest both as possible noninvasive markers of pulmonary fibrosis and because the increased values suggest that platelet activation may play a pathogenetic role in CFPD.

Adult↗
PubMed2003

Autoantibodies in mothers of children with neonatal liver disease.

OBJECTIVES: Neonatal lupus erythematosus (NLE) is associated with maternal anti-Ro/La autoantibodies. It is characterized by heart block and/or cutaneous skin lesions, and occasionally liver disease. This study was performed to determine whether idiopathic neonatal cholestasis (INC) represents NLE without its cardiac or cutaneous findings. METHODS: Sera were obtained for autoantibody analysis from mothers of children with INC (N = 11), biliary atresia (N = 25), other liver disease excluding viral hepatitis (liver disease control subjects, N = 14), and healthy children (normal control subjects [NC], N = 22). RESULTS: The characteristic serologic findings of NLE, high titer antibodies to Ro and/or La, were absent in mothers from all groups. An unexpected finding was the prevalence of autoantibodies in mothers of infants with liver disease of any type. The frequency of maternal antinuclear antibodies at > or = 1:120 dilution was greater than the estimated frequency in the general population (22% vs. 9%, P = 0.044). The frequency of maternal low titer autoantibodies to 52 kD Ro detected by ELISA was significantly greater than in the NC group (31% vs. 5%, P = 0.014). CONCLUSIONS: The majority of cases of INC do not represent NLE. The frequent presence of autoantibodies in mothers of infants in all neonatal liver disease groups raises the possibility that maternal serologic autoimmunity is associated with neonatal liver disease.

Adult↗
PubMed2002

Response of elevated Epstein-Barr virus DNA levels to therapeutic changes in pediatric liver transplant patients: 56-month follow up and outcome.

BACKGROUND: Posttransplant lymphoproliferative disease (PTLD) is a serious complications after liver transplantation. Epstein-Barr virus (EBV) load measured by quantitative competitive polymerase chain reaction (PCR) has been used as an early marker for the development of PTLD and a guide for initiating preemptive therapy. The aim of this study is to report the results of EBV DNA PCR screening in a transplant population and to examine the risk factors for developing elevated EBV DNA PCR and the effect of interventions for reducing EBV DNA levels. METHODS: Medical records of 44 children who underwent liver transplantation and EBV DNA PCR screening during a 3-year period were reviewed, and the patients were prospectively followed up for another 2 years. Eleven patients who developed elevated EBV DNA PCR levels, defined as >/=40 genomes/105 peripheral blood lymphocytes (PBL) in pretransplant EBV-seronegative patients and >/=200 genomes/105 PBL in pretransplant-seropositive patients, were treated. The initial intervention was reduction of immunosuppression and initiation of anti-viral therapy in all patients, with administration of cytomegalovirus immunoglobulin (CMV-IgG) in two patients. CMV-IgG was then given to five of the patients who did not respond to the initial intervention. RESULTS: The initial intervention resulted in the reduction of EBV DNA PCR levels to below threshold values in 4 of 11 patients. Five patients who did not respond to the initial interventions were subsequently given intravenous CMV-IgG. The EBV DNA PCR level fell in all five of these patients during the course of treatment with CMV-IgG, with a significant reduction (to threshold levels or by two dilutions) in four of the five patients. No episodes of graft rejection were observed. CONCLUSION: Eleven patients (25%) developed elevated EBV DNA PCR after liver transplantation. There were no identifiable risk factors for developing elevated EBV DNA PCR. A combination of reducing immunosuppression, adding antiviral agents, and initiating CMV-IgG resulted in a significant reduction of EBV DNA levels in nine (82%) patients during the follow-up period.

Adolescent↗
PubMed2002

Niemann-pick disease type C in neonatal cholestasis at a North American Center.

OBJECTIVE: To determine the frequency of Niemann-Pick disease type C (NPC) among children being evaluated for neonatal cholestasis during a 2-year period. METHODS: Medical records were reviewed from all infants with cholestasis and all patients with NPC evaluated at our center from January 1997 through December 1998. RESULTS: Forty neonates with cholestasis were evaluated, including three patients diagnosed with NPC (age at diagnosis, 5-21 months) who were originally labeled as having idiopathic neonatal cholestasis (INH). Two adolescents (ages 14 and 16 years) were also diagnosed with NPC during this period, one who originally had neonatal hepatitis and cirrhosis, and the other who had hepatosplenomegaly throughout childhood. Three of the patients with NPC were Hispanic. At time of NPC diagnosis, infants had mildly delayed motor development and persistent splenomegaly with or without hepatomegaly, and the adolescents had ataxia, dysarthria, hepatosplenomegaly, and paresis of vertical gaze. The diagnosis of NPC was established by demonstrating defective cellular cholesterol esterification in cultured skin fibroblasts in three patients and a specific genetic mutation in three patients. Niemann-Pick disease type C was found in 27% of infants initially diagnosed with INH and 8% of all infants evaluated for cholestasis. CONCLUSION: Niemann-Pick disease type C should be considered in all infants with cholestasis, particularly those with splenomegaly or who are of Hispanic descent. Electron microscopy and lipid analysis of liver biopsy specimens obtained during the evaluation of neonatal cholestasis may suggest this diagnosis.

Adolescent↗