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Dive into the research topics where M. James Lopez is active.

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Featured researches published by M. James Lopez.


Pediatric Transplantation | 2010

Assessment of transition readiness skills and adherence in pediatric liver transplant recipients

Emily M. Fredericks; Dawn Dore-Stites; Andrew Well; John C. Magee; Gary L. Freed; Victoria Shieck; M. James Lopez

Fredericks EM, Dore‐Stites D, Well A, Magee JC, Freed GL, Shieck V, Lopez MJ. Assessment of transition readiness skills and adherence in pediatric liver transplant recipients.
Pediatr Transplantation 2010: 14:944–953.


Pediatric Transplantation | 2008

Adherence and health-related quality of life in adolescent liver transplant recipients

Emily M. Fredericks; John C. Magee; Lisa Opipari-Arrigan; Victoria Shieck; Andrew Well; M. James Lopez

Abstract:  Adolescence is a particularly high‐risk period for non‐adherence with post‐transplant medical regimens. There remains a lack of research investigating factors related to non‐adherence in adolescent LT recipients. The present study empirically assessed the relationship between adherence and HRQOL in adolescent LT recipients. Participants included 25 adolescents (mean = 15.1 yr, range 12–17.9) and their parent/guardian(s). Adherence was assessed using multiple indices including clinician‐conducted interviews, rate of clinic attendance, and s.d. of consecutive tacrolimus blood levels. HRQOL was examined using self‐report and parent‐proxy report on well‐validated assessment measures. Results indicated that 76% of participants were non‐adherent on at least one measure of adherence, and HRQOL was significantly lower than normative data for healthy children. Tacrolimus s.d. were significant related to poor HRQOL across domains of physical, school, and social functioning. Non‐adherent adolescents reported poorer health perceptions, self‐esteem, mental health, family cohesion, and more limitations in social and school activities related to physical, emotional, and behavioral problems. These results suggest that empirically based assessment of HRQOL may help identify those at highest risk for behavior, emotional and school difficulties, as well as non‐adherence. The examination of tacrolimus s.d. may also help identify patients who may benefit from intervention to promote adherence and HRQOL. Prospective investigations are necessary to further identify the impact of HRQOL on adherence and long‐term health outcomes to further guide clinical intervention.


Hepatology | 2013

Intravenous N-acetylcysteine in pediatric patients with nonacetaminophen acute liver failure: A placebo-controlled clinical trial

Robert H. Squires; Anil Dhawan; Estella M. Alonso; Michael R. Narkewicz; Benjamin L. Shneider; Norberto Rodriguez-Baez; Dominic Dell Olio; Saul J. Karpen; Steven J. Lobritto; Elizabeth B. Rand; Philip J. Rosenthal; Simon Horslen; Vicky L. Ng; Girish Subbarao; Nanda Kerkar; David A. Rudnick; M. James Lopez; Kathleen B. Schwarz; Rene Romero; Scott A. Elisofon; Edward Doo; Patricia R. Robuck; Sharon Lawlor; Steven H. Belle

N‐acetylcysteine (NAC) was found to improve transplantation‐free survival in only those adults with nonacetaminophen (non‐APAP) acute liver failure (ALF) and grade 1‐2 hepatic encephalopathy (HE). Because non‐APAP ALF differs significantly between children and adults, the Pediatric Acute Liver Failure (PALF) Study Group evaluated NAC in non‐APAP PALF. Children from birth through age 17 years with non‐APAP ALF enrolled in the PALF registry were eligible to enter an adaptively allocated, doubly masked, placebo‐controlled trial using a continuous intravenous infusion of NAC (150 mg/kg/day in 5% dextrose in water [D5W]) or placebo (D5W) for up to 7 days. The primary outcome was 1‐year survival. Secondary outcomes included liver transplantation‐free survival, liver transplantation (LTx), length of intensive care unit (ICU) and hospital stays, organ system failure, and maximum HE score. A total of 184 participants were enrolled in the trial with 92 in each arm. The 1‐year survival did not differ significantly (P = 0.19) between the NAC (73%) and placebo (82%) treatment groups. The 1‐year LTx‐free survival was significantly lower (P = 0.03) in those who received NAC (35%) than those who received placebo (53%), particularly, but not significantly so, among those less than 2 years old with HE grade 0‐1 (NAC 25%; placebo 60%; P = 0.0493). There were no significant differences between treatment arms for hospital or ICU length of stay, organ systems failing, or highest recorded grade of HE. Conclusion: NAC did not improve 1‐year survival in non‐APAP PALF. One‐year LTx‐free survival was significantly lower with NAC, particularly among those <2 years old. These results do not support broad use of NAC in non‐APAP PALF and emphasizes the importance of conducting controlled pediatric drug trials, regardless of results in adults. (HEPATOLOGY 2013)


Pediatrics | 2006

Detection of acetaminophen protein adducts in children with acute liver failure of indeterminate cause

Laura P. James; Estella M. Alonso; Linda S. Hynan; Jack A. Hinson; Timothy J. Davern; William M. Lee; Robert H. Squires; Norberto Rodriguez-Baez; Karen F. Murray; R. W. Shepherd; Phillip Rosenthal; Benjamin L. Schneider; Sukru Emre; Simon Horslen; Martin G. Martin; M. James Lopez; Brendan M. McGuire; Michael R. Narkewicz; Maureen M. Jonas; Kathleen B. Schwarz; Steven J. Lobritto; Daniel W. Thomas; Liz Rand; Anil Dhawan; Vicky L. Ng; Deirdre Kelly; Ruben E. Quiros; Joel E. Lavine; Humberto Soriano

OBJECTIVE. Acetaminophen cysteine protein adducts are a widely recognized correlate of acetaminophen-mediated hepatic injury in laboratory animals. The objective of this study was to use a new assay for the detection of acetaminophen cysteine protein adducts in children with acute liver failure to determine the role of acetaminophen toxicity in acute liver failure of unknown cause. METHODS. Serum samples from children with acute liver failure were measured for acetaminophen cysteine protein adducts using high-performance liquid chromatography with electrochemical detection. For comparison, samples from children with well-characterized acetaminophen toxicity and children with known other causes of acute liver failure also were measured for acetaminophen cysteine protein adducts. The analytical laboratory was blinded to patient diagnoses. RESULTS. Acetaminophen cysteine protein adduct was detected in 90% of samples from children with acute liver failure that was attributed to acetaminophen toxicity, 12.5% of samples from children with acute liver failure of indeterminate cause, and 9.6% of samples from children with acute liver failure that was attributed to other causes. Adduct-positive patients from the indeterminate cause subgroup had higher levels of serum aspartate aminotransferase and alanine aminotransferase and lower levels of bilirubin. Adduct-positive patients also had lower rates of transplantation and higher rates of spontaneous remission. CONCLUSIONS. A small but significant percentage of children with acute liver failure of indeterminate cause tested positive for acetaminophen cysteine protein adducts, strongly suggesting acetaminophen toxicity as the cause of acute liver failure. An assay for the detection of acetaminophen cysteine protein adducts can aid the diagnosis of acetaminophen-related liver injury in children.


Journal of Pediatric Gastroenterology and Nutrition | 2011

Characteristics of Idiosyncratic Drug-induced Liver Injury in Children: Results From the DILIN Prospective Study

Jean P. Molleston; Robert J. Fontana; M. James Lopez; David E. Kleiner; Jiezhun Gu; Naga Chalasani

Background: The spectrum and severity of idiosyncratic drug-induced liver injury (DILI) in children are not well established. Patients and Methods: The DILIN (Drug-Induced Liver Injury Network) Prospective Study is a longitudinal multicenter study designed to determine the etiologies, risk factors, and outcomes of suspected DILI. Between September 2004 and September 2009, 30 children ages 2 to 18 years with suspected DILI who met eligibility criteria were enrolled and studied for at least 6 months. Results: Mean age was 14 years; 70% were girls. Antimicrobial (50%) and central nervous system agents (40%) were the most commonly implicated drug classes, with minocycline (4), isoniazid (3), azithromycin (3), atomoxetine (3), and lamotrigine (3) the leading agents. Median time from drug initiation to symptom onset was 32 days. Peak (median) liver chemistries were aspartate aminotransferase 503 U/L, alanine aminotransferase 727 U/L, alkaline phosphatase 331 U/L, and total bilirubin 3.9 mg/dL. Autoantibodies were common (64%). Liver injury pattern was hepatocellular 78%, cholestatic 13%, and mixed 9%. The DILI episode was scored: mild 32%, moderate 44%, severe 20%, and fatal (within 6 months) 4%. Causality assessment was definite 36%, very likely 36%, probable 16%, possible 8%, and unlikely 4%. Seven percent had persistent liver test abnormalities at 6-month follow-up suggesting chronic DILI. Liver biopsies from 12 children most frequently demonstrated chronic hepatitis or bile duct injury. Conclusions: Idiosyncratic DILI in children is most commonly caused by antimicrobial or central nervous system agents and usually presents with a hepatocellular injury pattern. The majority of patients recover, but morbidity and infrequent mortality are seen.


Pediatric Transplantation | 2011

Transition of pediatric liver transplant recipients to adult care: Patient and parent perspectives

Emily M. Fredericks; Dawn Dore-Stites; M. James Lopez; Andrew Well; Victoria Shieck; Gary L. Freed; Sally J. Eder; John C. Magee

Fredericks EM, Dore‐Stites D, Lopez MJ, Well A, Shieck V, Freed GL, Eder SJ, Magee JC. Transition of pediatric liver transplant recipients to adult care: Patient and parent perspectives.
Pediatr Transplantation 2011: 15: 414–424.


Pediatric Transplantation | 2009

Serum α-NH2-butyric acid may predict spontaneous survival in pediatric acute liver failure

David A. Rudnick; Dennis J. Dietzen; Yumirle P. Turmelle; R. W. Shepherd; Song Zhang; Steven H. Belle; Rob Squires; Saul J. Karpen; Dominic Dell Olio; Robert H. Squires; Ben Schneider; Steven J. Lobritto; Maureen M. Jonas; Vick Ng; Girish Subbarao; Kathleen Schwartz; Anil Dhawan; Sukru Emre; Estella M. Alonso; Philip J. Rosenthal; Nada Yazigi; Michael R. Narkewicz; M. James Lopez; Liz Rand; Norberto Rodriguez Baez; Karen F. Murray; David Rudnick

Abstract:  ALF is a serious, often fatal condition. Up to half of PALF patients do not survive without liver transplantation; however, early identification of those least likely to survive spontaneously remains difficult. Clinical experience suggests that recovery from ALF depends on the ability of the liver to regenerate. Based on this, we hypothesized that bio‐markers of hepatic regeneration could have utility as predictors of recovery from PALF. In the studies reported here, we used comprehensive amino acid analysis to search for novel metabolomic markers of liver regeneration in mice subjected to partial hepatectomy. This analysis identified α‐NH2‐adipic acid and α‐NH2‐butyric acid as significantly increased in liver and plasma samples from mice subjected to partial hepatectomy compared to controls. Next, we tested whether serum levels of these markers were associated with clinical outcomes in PALF patients. This examination, performed on the initially collected serum samples from 40 randomly selected patients enrolled in the PALF Study Group, showed increased α‐NH2‐butyric‐acid (Aab) and Aab:leucine (Aab:Leu) ratio in patients who survived without transplantation compared to those who were transplanted or died. These data indicate that Aab and the Aab:Leu ratio may predict clinical outcomes in PALF.


Pediatric Clinics of North America | 2003

Immunization of children after solid organ transplantation.

M. James Lopez; Susan E. Thomas

The array of immunizations commonly used in childhood has risen in an attempt to prevent many of the potentially serious infections of infancy and childhood. In this article, the authors provide rational guidelines for vaccination of these children. The authors briefly review the susceptibilities caused by immunosuppression in these patients, discuss the problems with various immunizations, and make individual recommendations regarding the use of each vaccine. Most recommendations are based on inferences from populations that may not be directly comparable to the transplantation population (patients with HIV or cancer or patients who have undergone bone marrow transplant), from case reports, and from small series of patients. The best recommendations ultimately must await the results of controlled trials of immunization.


Liver Transplantation | 2012

Relationship Between Sleep Problems and Health-Related Quality of Life Among Pediatric Liver Transplant Recipients

Emily M. Fredericks; Dawn Dore-Stites; Sheyla Y. Calderon; Andrew Well; Sally J. Eder; John C. Magee; M. James Lopez

Among adult liver transplant recipients (LTRs), sleep disturbances and fatigue are common. Sleep problems following pediatric liver transplantation may contribute to daytime fatigue and lower health‐related quality of life (HRQOL). The aim of this cross‐sectional study was to determine the impact of sleep problems on the HRQOL of pediatric LTRs using validated measures. Participants included 47 LTRs. Mean age of the LTRs was 10.9 ± 4.6 years, and mean time since transplantation was 6.2 ± 3.9 years. The primary indication for transplantation was biliary atresia (51%). According to parent reports, pediatric transplant recipients had symptoms of sleep‐disordered breathing, excessive daytime sleepiness, daytime behavior problems, and restless legs; 40.4% of parents and 43.8% of children reported significantly lower total HRQOL for the recipients. Age, time since transplantation, and health status were not significantly related to the quality of life. Hierarchical regression analyses revealed that the sleep‐disordered breathing subscale of the Pediatric Sleep Questionnaire accounted for significant variance in parent‐proxy reports on the Pediatric Quality of Life (PedsQL) summary scales measuring childrens psychosocial health (R2 = 0.36, P < 0.001), physical health (R2 = 0.19, P = 0.004), and total HRQOL (R2 = 0.35, P < 0.001). Also, the sleep‐disordered breathing subscale accounted for significant variance in the child self‐reported school functioning scale (R2 = 0.18, P = 0.03). Clinically significant sleep problems were more common among children with low total HRQOL. In conclusion, sleep problems were common in this cohort of pediatric LTRs and predicted significant variance in HRQOL. Prospective larger scale studies are needed to assess factors that contribute to sleep difficulties and low HRQOL in this population. The detection and treatment of significant sleep problems may benefit the HRQOL of pediatric LTRs. Liver Transpl 18:707–715, 2012.


Pediatric Transplantation | 2015

Assessing allocation of responsibility for health management in pediatric liver transplant recipients

Jacob L. Bilhartz; M. James Lopez; John C. Magee; Victoria Shieck; Sally J. Eder; Emily M. Fredericks

Given the increased risk for non‐adherence and poor health outcomes in late adolescence, there is a need for better methods to evaluate and improve the transition process as adolescent patients are prepared to be independent adults. This study assessed the psychometrics and concurrent validity of a newly developed measure of AoR for health management in pediatric liver transplant patients. A total of 48 patients and 37 parents completed a 13‐item measure of AoR. We performed an exploratory PCA on survey results and used component scores to assess the relationship between AoR and age, age at transplant, adherence, and health outcomes. Two primary components were identified: communication with the healthcare system and self‐management tasks. Parent perception of adolescent responsibility for tasks related to communicating with the healthcare system was correlated, in younger patients, with increased non‐adherence while responsibility for tasks related to self‐management was correlated, in older patients, with decreased non‐adherence. These results support AoR as a two‐domain construct, and they provide targets for monitoring and intervention as adolescent patients advance toward transfer.

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Estella M. Alonso

Children's Memorial Hospital

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Michael R. Narkewicz

University of Colorado Denver

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Andrew Well

University of Michigan

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