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Biomedical subjects

Peter F Whitington

Publications and source records attributed to Peter F Whitington.

At least 19 recordsLinked to original sources
PubMed2006

Surgically restoring portal blood flow to the liver in children with primary extrahepatic portal vein thrombosis improves fluid neurocognitive ability.

OBJECTIVES: Children with primary extrahepatic portal vein thrombosis (EHPVT) have portal-systemic shunting, which may lead to disturbed neurocognitive function similar to portal-systemic encephalopathy (PSE) seen with chronic liver disease and cirrhosis. The functions most affected are those involving fluid cognitive ability, which comprise neurocognitive domains such as attention, processing speed, and short-term memory, that are particularly vulnerable to systemic illness or diffuse neurologic insult. We determined the fluid cognitive ability of children with EHPVT and whether surgically restoring portal blood flow by mesenteric left portal vein bypass (MLPVB) improved it. DESIGN: Twelve children with EHPVT and no overt PSE underwent comprehensive neurocognitive testing before and 1 year after undergoing surgery with intent to perform MLPVB. The evaluations sampled 4 functional domains at both time points: (1) neurobehavioral (behavior, emotional, executive functioning); (2) broad cognitive (intelligence, achievement); (3) fluid ability (attention, mental speed, working memory, memory encoding); and (4) visual motor (drawing, fine motor). Tasks in the fluid-ability and visual-motor domains were expected to be especially sensitive to adverse effects of EHPVT and to be most likely to show improvement with MLPVB. The test group consisted of 8 subjects who underwent successful MLPVB, and the comparison group was composed of 3 patients who received distal splenorenal shunts and one whose MLPVB failed. RESULTS: Both groups demonstrated similar fluid cognitive ability at initial evaluation. Successful MLPVB resulted in significantly improved fluid cognitive function: in the fluid cognitive domain, significant improvements were seen for the hit reaction time variability in the Conner's Continuous Performance Test, the attention scale of the Cognitive Assessment System, and immediate verbal memory in the Children's Memory Scale. In the visual-motor domain, z scores on the Grooved Pegboard Test improved. No improvement was observed in the comparison group. DISCUSSION: The results show that surgically restoring portal flow to the liver in children with primary EHPVT results in improved fluid cognitive ability. Subjects showed some neurocognitive abnormalities involving mainly fluid cognitive ability consistent with minimal PSE seen in adults with chronic liver disease. Cognitive defects in patients with minimal PSE seem to relate primarily to attention and fine motor skill, and although affected patients can function in everyday life, they are at risk for performance deficits in educational and vocational situations requiring the ability to pay close attention and react quickly (eg, driving, employment in manufacturing). The tests we administered in these domains are pediatric equivalents to measures used to detect minimal PSE in adults and should detect abnormalities in the same functional domains. Our results suggest that a narrow battery of tests could be used to detect minimal PSE in children in a manner similar to the 5-test battery used in adults, eliminating the need for the comprehensive and broad testing we performed. Our findings suggest that shunting of portal blood from the liver in primary EHPVT can result in PSE and question whether it is as benign a disease as previously thought. The importance of our findings is twofold. For understanding the pathophysiology of PSE, we have shown that restoring blood flow to the liver improves cognitive function in children with EHPVT. For therapy for EHPVT, it becomes clear that MLPVB is an excellent treatment option. It is effective for treating the complications of portal hypertension and provides effective portal blood flow that other medical and surgical therapies do not. The findings provide additional evidence that primary EHPVT should be considered curable by MLPVB. However, comparison of overall risks and benefits of MLPVB with those of other therapeutic options and longer-term outcome studies must be completed before MLPVB can be fully endorsed as the best treatment for EHPVT in children. CONCLUSIONS: Surgical restoration of portal venous flow to the liver in children with primary EHPVT by MLPVB improves fluid cognitive ability. MLPVB should be considered in treating primary EHPVT, because it corrects portal blood flow and could optimize learning potential.

Anastomosis, Surgical↗
PubMed2006

Roles of phosphatidylinositol 3-kinase and osteopontin in steatosis and aminotransferase release by hepatocytes treated with methionine-choline-deficient medium.

Feeding mice a methionine and choline-deficient (MCD) diet serves as an experimental animal model for nonalcoholic steatohepatitis (NASH). In the present study we examined the effect of exposing AML-12 hepatocytes to MCD culture medium in regard to mechanisms of steatosis and alanine amino-transferase (ALT) release. Cells exposed to MCD medium developed significant and progressive steatosis from 6 to 24 h and also had significantly increased loss of ALT into the medium at 18 and 24 hours of incubation. No increased oxidative injury or cell death was observed. Osteopontin (OPN) mRNA in cells and protein expression in medium were significantly increased during 6-24 hours of incubation. MCD medium treatment also resulted in activation of PI3-kinase by 30 minutes and its downstream target p-Akt within 1hour of incubation. Steatosis was associated with increased expression of microsomal triglyceride transfer protein (MTTP) mRNA and increased ALT release with over expression of ALT mRNA, all of which were completely prevented by inhibition of PI3-kinase (LY294002). Blocking OPN signaling by treating with anti-OPN or anti-beta3-integrin antibody prevented the increased ALT release while only partially prevented the increased ALT mRNA expression, but had no effect on either steatosis or MTTP expression. In conclusion, incubation of cultured hepatocytes with MCD medium results in cellular steatosis and OPN dependent ALT release. PI3-kinase plays a central role in signaling the MCD medium-induced steatosis and increased OPN expression, whereas OPN appears to play a role in signaling hepatocyte ALT release but not steatosis.

Animals↗
PubMed2006

Hepatocellular carcinoma in ten children under five years of age with bile salt export pump deficiency.

Hepatocellular carcinoma (HCC) is rare in young children. We attempted to see if immunohistochemical and mutational-analysis studies could demonstrate that deficiency of the canalicular bile acid transporter bile salt export pump (BSEP) and mutation in ABCB11, encoding BSEP, underlay progressive familial intrahepatic cholestasis (PFIC)--or "neonatal hepatitis" suggesting PFIC--that was associated with HCC in young children. We studied 11 cases of pediatric HCC in the setting of PFIC or "neonatal hepatitis" suggesting PFIC. Archival liver were retrieved and immunostained for BSEP. Mutational analysis of ABCB11 was performed in leukocyte DNA from available patients and parents. Among the 11 nonrelated children studied aged 13-52 months at diagnosis of HCC, 9 (and a full sibling, with neonatal hepatitis suggesting PFIC, of a tenth from whom liver was not available) had immunohistochemical evidence of BSEP deficiency; the eleventh child did not. Mutations in ABCB11 were demonstrated in all patients with BSEP deficiency in whom leukocyte DNA could be studied (n = 7). These mutations were confirmed in the parents (n = 14). With respect to the other 3 children with BSEP deficiency, mutations in ABCB11 were demonstrated in all 5 parents in whom leukocyte DNA could be studied. Thirteen different mutations were found. In conclusion, PFIC associated with BSEP deficiency represents a previously unrecognized risk for HCC in young children. Immunohistochemical evidence of BSEP deficiency correlates well with demonstrable mutation in ABCB11.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2006

A multicenter study of the outcome of biliary atresia in the United States, 1997 to 2000.

OBJECTIVE: To determine the prognostic factors and optimal approaches to the diagnosis and management of biliary atresia, the leading indication for liver transplantation in children. STUDY DESIGN: A retrospective study was performed of all children who underwent hepatoportoenterostomy (HPE) for biliary atresia between 1997 and 2000 at 9 centers in the United States. Outcome at age 24 months was correlated with demographic and clinical parameters. RESULTS: A total of 104 children underwent HPE; 25% had congenital anomalies, and outcome was worse in those with biliary atresia splenic malformation syndrome. Diagnostic and clinical approaches varied, although specific approaches did not appear to correlate with outcome. The average age at referral was 53 days, and the average age at HPE was 61 days. At age 24 months, 58 children were alive with their native liver, 42 had undergone liver transplantation (37 alive, 5 dead), and 4 had died without undergoing transplantation. Kaplan-Meier analysis of survival without liver transplantation revealed markedly improved survival in children with total bilirubin level<2 mg/dL at 3 months after HPE (84% vs 16%; P<.0001). CONCLUSIONS: Outcome in the study centers was equivalent to that reported in other countries. Total bilirubin in early follow-up after HPE was highly predictive of outcome. Efforts to improve bile flow after HPE may lead to improved outcome in children with biliary atresia.

Abnormalities, Multiple↗
PubMed2006

Correction of extrahepatic portal vein thrombosis by the mesenteric to left portal vein bypass.

OBJECTIVE: The goal of this study was to determine the effectiveness of mesenteric vein to left portal vein bypass operation (MLPVB) in correcting extrahepatic portal vein thrombosis (EHPVT) in children. The treatment of idiopathic EHPVT has been primarily palliative, whereas MLPVB restores hepatic portal flow in patients with EHPVT. METHODS: Thirty-four children with symptomatic EHPVT underwent surgery with intent to perform MLPVB and were followed for up to 7 years. MLPVB was successful in 31 patients (91%), all of whom maintain patent vein grafts and have symptomatic relief of EHPVT in follow-up. All patients had complete relief from gastrointestinal bleeding. Patients with hypersplenism had significant increases in platelet and leukocyte counts and reduction in spleen size. Superior mesenteric vein flow increased from 119 +/- 66 mL/min before bypass to 447 +/- 225 mL/min (P < 0.0001) after surgery. Postoperative blood flow in the bypass graft expressed as a fraction of calculated ideal portal flow for size correlated inversely with age (P < 0.001). Left-portal vein diameter increased from 2.6 +/- 1.6 mm to 7.3 +/- 2.4 mm 2 years after surgery (P < 0.002). Liver volume increased from 703 +/- 349 cm3 to 799 +/- 351 cm3 1 week after surgery (P < 0.001). Prothrombin time improved to normal in all patients 1 year after surgery. CONCLUSIONS: MLPVB provides excellent relief of symptoms in children with idiopathic EHPVT and results in liver growth and normalization of coagulation parameters. This surgery is corrective and should be done at as early an age as possible.

Blood Pressure↗
PubMed2006

Neonatal liver disease.

Establishing a rapid and accurate diagnosis of the cause of neonatal liver disease is an urgent matter. The initial detection of this condition relies on the sensitivity of the primary care provider or pediatrician to the signs and symptoms of jaundice and abnormal stool and urine color. It is critical to evaluate jaundice in any infant older than 2 weeks with measurement of fractionated bilirubin, and further assessment is necessary if the direct value is above 1.0 mg/dL in the setting of a total bilirubin of less than 5.0 mg/dL or a direct bilirubin of more than 20% of total if the total is more than 5.0 mg/dL. A diagnostic algorithm for the evaluation of infants who meet these criteria can guide physicians in selecting appropriate and timely diagnostic testing and referral to pediatric gastroenterology for these patients, whose outcome will rely on rapid diagnosis.

Algorithms↗
PubMed2005

Carnitine treatment inhibits increases in cerebral carnitine esters and glutamate detected by mass spectrometry after hypoxia-ischemia in newborn rats.

BACKGROUND AND PURPOSE: Cerebral ischemic insults disrupt normal respiratory activity in mitochondria. Carnitine plays an essential role in mitochondrial metabolism and in modulating excess acyl-coenzyme A (acyl-CoA) levels. The effects of cerebral ischemia on carnitine metabolism are not well understood, although the newborn may be particularly vulnerable to carnitine deficiency. We used a newborn rat model of hypoxia-ischemia (HI) to test the hypothesis that HI alters acyl-CoA:CoA homeostasis and that this effect can be prevented by treatment with carnitine. METHODS: A total of 120 postnatal day 7 rats were subjected to 70 minutes of HI after treatment with 16 mmol/kg intraperitoneal l-carnitine or diluent. Carnitine, acylcarnitines, and excitatory amino acids were measured by mass spectrometry, and carnitine acetyl transferase activity, superoxide, and levels of the mitochondrial phospholipid cardiolipin (CL) were measured at 2- and 24-hour recovery. RESULTS: HI and hypoxia were associated with a significant increase in the ratio of acyl-CoA:CoA, which was prevented by treatment with carnitine. Carnitine treatment also prevented increases in glutamate, glycine, superoxide, and decrease of CL. CONCLUSIONS: Carnitine metabolic pathways are compromised in HI and hypoxia. The protective effect of carnitine treatment on HI injury may be attributable to maintaining mitochondrial function.

Animals↗
PubMed2005

Disparate clinical presentation of neonatal hemochromatosis in twins.

Neonatal hemochromatosis (NH) is a rare disease of gestation that results in fetal liver injury and extrahepatic siderosis. The etiology of NH is not fully understood. However, the rate of recurrence of NH in the pregnancy after an affected one is approximately 80%. A spectrum of liver disease has been recognized, spanning from liver failure in the fetus or neonate to infants that survive with medical therapy. Here we report on 2 sets of fraternal twins, each set with a gross disparity in the severity of presentation: 1 infant with liver failure and the other nearly unaffected. These findings suggest a need to look carefully for subclinical disease in the siblings of patients with NH by using sensitive tests such as those for ferritin and alpha-fetoprotein. They also suggest that affected infants may be missed when using routine clinical testing, which would lead to the apparent rate of recurrence, understating the actual recurrence rate.

Diseases in Twins↗
PubMed2005

Expression of osteopontin correlates with portal biliary proliferation and fibrosis in biliary atresia.

The acquired or perinatal form of biliary atresia is a Th1 fibro-inflammatory disease affecting both the extrahepatic and intrahepatic bile ducts. Osteopontin (OPN) is a Th1 cytokine implicated in several fibro-inflammatory and autoimmune diseases. We examined the expression of OPN in acquired biliary atresia in comparison to normal liver and several pediatric cholestatic liver diseases. We also assessed OPN expression by cultured human bile duct epithelial cells. We found that liver OPN mRNA and protein expression were significantly increased in biliary atresia versus normal and other cholestatic diseases. OPN expression in biliary atresia was localized to epithelium of proliferating biliary structures (ductules and/or ducts) and bile plugs contained therein. No portal biliary OPN expression could be demonstrated in normal liver, syndromic biliary atresia, biliary obstruction not due to biliary atresia, and idiopathic neonatal hepatitis. OPN expression by human bile duct epithelial cells in culture was responsive to IL-2 and TNF-alpha. Our results demonstrate an up-regulation of OPN expression by interlobular biliary epithelium in biliary atresia, which correlates with biliary proliferation and portal fibrosis. These findings suggest a role for OPN in the pathogenesis of biliary atresia.

Base Sequence↗
PubMed2005

Steatohepatitis develops rapidly in transgenic mice overexpressing Abcb11 and fed a methionine-choline-deficient diet.

Nonalcoholic fatty liver disease is the most common reason for abnormal liver chemistries in the United States. The factors that lead from benign steatosis to nonalcoholic steatohepatitis are poorly understood. Transthyretin-Abcb11 (TTR-Abcb11) transgenic mice overexpress the bile salt transporter Abcb11 and hypersecrete biliary lipids. Thus the aim of this study is to employ feeding of the methionine-choline-deficient (MCD) diet to TTR-Abcb11 transgenic mice to further determine the mechanisms responsible for the development of steatohepatitis. FVB/NJ and TTR-Abcb11 mice were fed control or MCD diets for up to 30 days. Serum aminotransferase levels, serum and hepatic triglyceride content, cytokines, markers of oxidative stress, and expression of selective genes were examined. MCD diet-fed TTR-Abcb11, but not wild-type, mice have elevated serum aminotransferase levels when compared after 7 days. They also have significantly lower hepatic triglyceride levels at all time points studied. After 14 days on the MCD diet, TTR-Abcb11 mice have 3-fold increases in TNF-alpha mRNA and 3.9-fold increases in IL-6 mRNA compared with FVB/NJ mice. TTR-Abcb11 mice also had a greater increase in cytochrome P-450 2E1 expression. A greater decrease in sterol regulatory element binding protein-1c and fatty acid synthase mRNA expression was also seen in TTR-Abcb11 compared with wild-type mice fed an MCD diet. They also have enhanced TNF-alpha, IL-6, and cytochrome P-450 2E1 expression. We conclude that TTR-Abcb11 mice develop a more rapid hepatitis with less steatosis.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Presence of multiple bile ducts in the liver graft increases the incidence of biliary complications in pediatric liver transplantation.

We studied the impact of multiple bile duct anastomosis on the development of biliary complications after liver transplantation in children. A total of 101 patients received a primary liver transplant and were divided into 2 groups: those with a single bile duct (n = 77) and those with multiple bile ducts (n = 24). Mean follow-up was 39.8 +/- 20.8 months. A total of 27 patients presented with biliary complications (26.7%), 18 patients (18.7%) presented with early complications (12 leaks and 6 strictures), and 9 patients (8.9%) had late strictures. Hepatic artery thrombosis (HAT) and multiple bile ducts were significant risk factors for the development of biliary complications, and the presence of multiple bile ducts was an independent risk factor. Patients with multiple bile ducts had a significantly greater incidence of total biliary complications compared to those with single ducts. Patients with multiple ducts had a higher incidence of leaks when compared to those in the single duct group, but the incidence of strictures, both early and late, was similar in both groups. One-year patient and graft survivals were not statistically different in the 2 groups. In conclusion, the presence of more than one bile duct in the graft is an independent risk factor for the development of biliary complications after pediatric liver transplantation.

Anastomosis, Surgical↗
PubMed2005

Autologous hematopoietic stem cell transplantation in patients with refractory Crohn's disease.

BACKGROUND & AIMS: Crohn's disease (CD) is an immunologically mediated inflammatory disease of the gastrointestinal tract. Due to a high morbidity and/or an increase in mortality in refractory cases, a new treatment approach is needed. In theory, maximum immune ablation by autologous hematopoietic stem cell transplantation (HSCT) can induce a remission. METHODS: We conducted a phase 1 HSCT study in 12 patients with refractory CD. Candidates were younger than 60 years of age with a Crohn's Disease Activity Index (CDAI) of 250-400 despite conventional therapies including infliximab. Peripheral blood stem cells were mobilized with cyclophosphamide and granulocyte colony-stimulating factor and CD34 + enriched. The immune ablative (conditioning) regimen consisted of 200 mg/kg cyclophosphamide and 90 mg/kg equine antithymocyte globulin. RESULTS: The procedure was well tolerated with anticipated cytopenias, neutropenic fever, and disease-related fever, diarrhea, anorexia, nausea, and vomiting. The median days for neutrophil and platelet engraftment were 9.5 (range, 8-11) and 9 (range, 9-18), respectively. The initial median CDAI was 291 (range, 250-358). Symptoms and CDAI improved before hospital discharge, whereas radiographic and colonoscopy findings improved gradually over months to years following HSCT. Eleven of 12 patients entered a sustained remission defined by a CDAI < or =150. After a median follow-up of 18.5 months (range, 7-37 months), only one patient has developed a recurrence of active CD, which occurred 15 months after HSCT. CONCLUSIONS: Autologous HSCT may be performed safely and has a marked salutary effect on CD activity. A randomized study will be needed to confirm the efficacy of this therapy.

Adolescent↗
PubMed2005

Intracranial vascular abnormalities in patients with Alagille syndrome.

OBJECTIVES: To define the spectrum of intracranial events and cerebrovascular lesions in patients with Alagille syndrome using magnetic resonance imaging with angiography of the head and medical histories and to correlate the presence of lesions with the clinical outcome of bleeding or ischemic intracranial events. METHODS: 26 patients with Alagille syndrome underwent magnetic resonance imaging with angiography of the head; 22 had no symptoms and underwent study for screening purposes and 4 were symptomatic with neurologic changes. The results of studies and the history of ischemic intracranial events were reviewed. RESULTS: Cerebrovascular abnormalities were detected in 10 of 26 (38%) patients (9 by head magnetic resonance imaging with angiography and 1 by necropsy). The findings included stenoses of the internal carotid arteries unilaterally (n = 5) or bilaterally (n = 3), basilar artery aneurysm (n = 1) and middle cerebral artery aneurysm (n = 1). Among the 9 patients with cerebrovascular abnormalities detected by magnetic resonance imaging with angiography, 5 had no symptoms (23%, 5 of 22) and 4 were symptomatic. Thus, 100% of symptomatic patients had detected abnormalities and 23% of screened, asymptomatic patients had detected anomalies. Screening magnetic resonance imaging with angiography failed to detect vascular anomalies in 2 asymptomatic patients who had fatal ischemic intracranial events years later. There was evidence of progression of vascular abnormalities in 4 patients. Ischemic intracranial events occurred in 10 of 26 (38%) patients and were associated with cerebrovascular abnormalities in 6 of 10 patients. CONCLUSION: The cerebral vasculopathy of Alagille syndrome predominantly involves the internal carotid arteries. It is more prevalent than would be suggested by the number of symptomatic individuals, appears to be progressive and shares many similarities with moyamoya. Magnetic resonance imaging with angiography is useful to detect these lesions and may have a valuable role in screening for treatable lesions such as aneurysms.

Adolescent↗
PubMed2005

Neonatal hemochromatosis: fetal liver disease leading to liver failure in the fetus and newborn.

Acute liver failure in the newborn is relatively rare but often fatal. The broadest definition of acute liver failure is failure of the vital functions of the liver occurring within weeks or a few months of the onset of clinical liver disease. Therefore, by definition, any liver failure in the newborn can be construed to be acute liver failure. A second component of the general definition of acute liver failure is the lack of known preexisting liver disease. In the case of neonatal acute liver failure, preexisting disease would by definition be liver disease that affects the fetus. Almost nothing is known about fetal onset liver failure, and there is no literature addressing the subject. This review will address fetal liver disease that leads to liver failure in the fetus or newborn.

Female↗
PubMed2005

Regional variation and use of exception letters for cadaveric liver allocation in children with chronic liver disease.

The Pediatric End-Stage Liver Disease (PELD) score was designed to reduce subjectivity in liver allocation and to advantage patients with a higher probability of waiting list mortality. The aims of this study were to determine the impact of PELD implementation for children with chronic liver disease and to assess whether PELD met its goal of standardization of liver allocation for children. This study used data reported to the United Network for Organ Sharing (UNOS) registry for children with chronic liver disease receiving primary cadaveric liver transplant between January 2000 and December 2001 (pre-PELD) and March 2002 and July 2003 (PELD). PELD reduced the percentage of children transplanted while in an intensive care unit and as status 1. A calculated PELD score was used for allocation in only 52% of recipients. Thirty percent were status 1 at transplant and PELD scores granted by exception were used for allocation in 18% of patients. There was regional variation in PELD score at allocation and use of exception scores with a significant relationship between PELD score and percentage of exception cases. Regional variation suggests that PELD has not resulted in standardization of listing practices in pediatric liver transplantation.

Cadaver↗