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Objectives To assess longitudinal neurocognitive development after liver transplantation and evaluate factors associated with neurocognitive performance. Study design Data from neurocognitive testing of 65 children (aged 1 year (n = 35), those who did so at age 80 mL/kg (P = .004; adjusted for age at transplantation: P = .046) were associated with FSIQ. Conclusions Young age at transplantation and large blood transfusions during transplantation are risk factors for poor neurocognitive performance later in life. Children who undergo transplantation before 1 year of age have significantly lower neurocognitive performance compared with those who do so later in childhood. Cognitive performance did not improve over time after transplantation.

Objectives: The importance of case load for treatment of extrahepatic biliary atresia (BA) is debated. The aim of this study was to register results of BA treatment in a small volume centre. Methods: Retrospective chart review study of patients with BA treated from 2000 to 2017. The institutional review board approved the study. Results: 45 babies were identified of which 42 (93%) are alive. 41 patients had a Kasai portoenterostomy (PE), two a hepaticojejunostomy and two a primary liver transplantation. The age at PE/hepaticojejunostomy was median 63 (4-145 days). Seven surgeons performed the operations, and the median duration of the diagnostic work-up was 8 (3-24) days. Clearance of jaundice was achieved in 23/43 (53%) babies, and 3- and 5-year native liver survival was 47% and 40% respectively. Clearance of jaundice post PE/hepaticojejunostomy was a strong predictor of native liver survival (adjusted OR: 0.027; 95%; P=0.009). Plasma level of conjugated bilirubin at time of referral was also a significant predictor of native liver survival (adjusted OR: 1.053; P=0.017). Conclusion: A small volume centre may achieve satisfactory results for BA patients. The study has, however, identified factors that may further improve results; earlier referral, optimizing diagnostic work-up, and establishing one dedicated surgical team.

AIM AND BACKGROUND: The Nordic Liver Transplant Registry (NLTR) accounts for all liver transplants performed in the Nordic countries since the start of the transplant program in 1982. Due to short waiting times, donor liver allocation has been made without considerations of the model of end-stage liver disease (MELD) score. We aimed to summarize key outcome measures and developments for the activity up to December 2013.MATERIALS AND METHODS: The registry is integrated with the operational waiting-list and liver allocation system of Scandiatransplant (www.scandiatransplant.org) and accounted at the end of 2013 for 6019 patients out of whom 5198 were transplanted. Data for recipient and donor characteristics and relevant end-points retransplantation and death are manually curated on an annual basis to allow for statistical analysis and the annual report.RESULTS: Primary sclerosing cholangitis, acute hepatic failure, alcoholic liver disease, primary biliary cirrhosis and hepatocellular carcinoma are the five most frequent diagnoses (accounting for 15.3%, 10.8%, 10.6%, 9.3% and 9.0% of all transplants, respectively). Median waiting time for non-urgent liver transplantation during the last 10-year period was 39 days. Outcome has improved over time, and for patients transplanted during 2004-2013, overall one-, five- and 10-year survival rates were 91%, 80% and 71%, respectively. In an intention-to-treat analysis, corresponding numbers during the same time period were 87%, 75% and 66%, respectively.CONCLUSION: The liver transplant program in the Nordic countries provides comparable outcomes to programs with a MELD-based donor liver allocation system. Unique features comprise the diagnostic spectrum, waiting times and the availability of an integrated waiting list and transplant registry (NLTR).

EBV after pediatric LT is a risk factor for PTLD. We wanted to evaluate the effect of intravenous ganciclovir on EBV viremia and to identify risk factors for chronic EBV viremia. All pediatric patients who underwent LT in Norway from 2002 until 2015 were reviewed. Twenty-two of 38 patients with viremia were treated with intravenous ganciclovir for a median of 22 (21-38) days. Treated and untreated patients were not different with respect to EBV seroconversion prior to transplantation or age at transplantation, but treated patients had significantly earlier viremia after transplantation (P=.005). There was no difference in the proportion of patients with reduction in virus load in patients treated with ganciclovir compared to untreated patients at 8 weeks. After 1 year, five of 19 patients treated with ganciclovir and six of 14 untreated patients had reduced virus load compared to start of viremia (P=.27). In conclusion, treatment with intravenous ganciclovir did not change the proportion of patients with reduction in EBV load at 8 weeks and 1 year after viremia. Younger age at transplantation, short time from transplantation to viremia, and lack of EBV seroconversion prior to transplantation were significant predictors of chronic EBV viremia.

Ischemic vascular complications and rejection occur more frequently with pediatric liver transplants versus adult liver transplants. Using intrahepatic microdialysis catheters, we measured lactate, pyruvate, glucose, and glycerol values at the bedside for a median of 10 days in 20 pediatric liver grafts. Ischemia (n = 6), which was defined as a lactate level > 3.0 mM and a lactate/pyruvate ratio > 20, was detected without a measurable time delay with 100% sensitivity and 86% specificity. Rejection (n = 8), which was defined as a lactate level > 2.0 mM and a lactate/pyruvate ratio < 20 lasting for 6 or more hours, was detected with 88% sensitivity and 45% specificity. With additional clinical criteria, the specificity was 83% without a decrease in the sensitivity. Rejection was detected at a median of 4 days (range = 1-7 days) before alanine aminotransferase increased (n = 5, P = 0.11), at a median of 4 days (range = 2-9 days) before total bilirubin increased 25% or more (n = 7, P = 0.04), and at a median of 6 days (range = 4-11 days) before biopsy was performed (n = 8, P = 0.05). In conclusion, microdialysis catheters can be used to detect episodes of ischemia and rejection before current standard methods in pediatric liver transplants with clinically acceptable levels of sensitivity and specificity. The catheters were well tolerated by the children, and no major complications related to the catheters were observed. Liver Transpl 19:305–314, 2013. © 2013 AASLD.

Biliary atresia (BA) is the most common indication for LT in children. We investigated whether this diagnosis per se, compared to other chronic liver diseases (OCLD), had an influence on patient survival. Data from 421 Scandinavian children, 194 with BA and 227 with OCLD, listed for LT between 1990 and 2010 were analyzed. The intention-to-treat survival and influencing risk factors were studied. Patients with BA had higher risk of death after listing than patients with OCLD. The youngest (1 year) and smallest (10 kg) children with the highest bilirubin (510 μmol/L), highest INR (1.6), and highest PELD score (20) listed during 1990s had the worst outcome. Given the same PELD score, patients with BA had higher risk of death than patients with OCLD. For adolescents, low weight/BMI was the only prognostic marker. Impaired intention-to-treat survival in patients with BA was mainly explained by more advanced liver disease in younger ages and higher proportion of young children in the BA group rather than diagnosis per se. PELD score predicted death, but seemed to underestimate the severity of liver disease in patients with BA. Poor nutritional status and severe cholestasis had negative impact on survival, supporting the "sickest children first" allocation policy and correction of malnutrition before surgery.

Rejection and ischemia are serious complications after liver transplantation. Early detection is mandatory, but specific markers are largely missing, particularly for rejection. The objective of this study was to explore the ability of microdialysis catheters inserted in liver grafts to detect and discriminate rejection and ischemia through postoperative measurements of inflammatory mediators. Microdialysis catheters with a 100-kDa pore size were inserted into 73 transplants after reperfusion. After the study's completion, complement activation product 5a (C5a), C-X-C motif chemokine 8 (CXCL8), CXCL10, interleukin-1 (IL-1) receptor antagonist, IL-6, IL-10, and macrophage inflammatory protein 1β were analyzed en bloc in all grafts with biopsy-confirmed rejection (n = 12), in grafts with vascular occlusion/ischemia (n = 4), and in reference grafts with a normal postoperative course of circulating transaminase and bilirubin levels (n = 17). The inflammatory mediators were elevated immediately after graft reperfusion and decreased toward low, stable values during the first 24 hours in nonischemic grafts. In grafts suffering from rejection, CXCL10 increased significantly (P = 0.008 versus the reference group and P = 0.002 versus the ischemia group) 2 to 5 days before increases in circulating alanine aminotransferase and bilirubin levels. The area under the receiver operating characteristic curve was 0.81. Grafts with ischemia displayed increased levels of C5a (P = 0.002 versus the reference group and P = 0.008 versus the rejection group). The area under the curve was 0.99. IL-6 and CXCL8 increased with both ischemia and rejection. In conclusion, CXCL10 and C5a were found to be selective markers for rejection and ischemia, respectively. Liver Transpl, 2012. © 2012 AASLD.

Acetylsalicylic acid is used in liver-transplanted children to prevent thrombosis of the hepatic artery. We evaluated whether acetylsalicylic acid and other risk factors were associated with bleeding after percutaneous liver biopsy.Medical charts, laboratory results, imaging studies, and anesthesia charts of 275 ultrasound-guided liver biopsy procedures in 190 children were reviewed. A total of 178 biopsies were performed on native livers and 97 on transplanted livers.Three major and 28 minor bleeding incidents were found. The mortality rate was 0%. Acetylsalicylic acid had been given the last 5 days before 55 of the biopsy procedures and no increased risk of bleeding was found (odds ratio 0.96 [0.37-2.26]; P = 1.00). Low-molecular-weight heparin and biopsies from focal lesions were risk factors for bleeding complications. Acute liver failure was associated with increased risk for major complications (odds ratio 26.1 [3.3-205]; P = 0.01) and was a risk factor for major bleeding. Postbiopsy ultrasound the day after the procedure (n = 266 [96% of 275 biopsies]) revealed minor bleeding after 7.1% of the biopsies and after 2.6% of the ultrasounds revealed unsuspected bleeding, but none of these required intervention.Ultrasound-guided liver biopsy in children is a procedure with a low rate of major complications and a high rate of minor bleeding not requiring intervention. Treatment with low-dose acetylsalicylic acid did not increase bleeding incidence or total complication rate. Low-molecular-weight heparin and biopsies from focal lesions were risk factors for bleeding complications. Routine ultrasound the day after the procedure did not change handling of the patients.

In neonates and infants with biliary obstruction, the diagnosis is important to establish early. Despite the use of several noninvasive imaging modalities, a definite diagnosis of biliary atresia (BA) or other pancreaticobiliary disorders may be difficult to ascertain. In this paper, we report our experience with endoscopic retrograde cholangiopancreaticography (ERCP) in the clinical situation of neonatal and infant jaundice.Between 1999 and 2006, we performed 23 ERCP procedures in 22 neonates and infants with the provisional diagnosis of biliary obstruction where other imaging was inconclusive. The mean age was 2.4 months and the mean weight was 4.8 kg. A pediatric videoendoscope with an outer diameter of 7.5 mm was used in all patients.ERCP was successful in 20 of 23 patients. BA was suggested in 6 patients, all subsequently verified by surgery. Detailed visualization of biliary structures important for planning of treatment was performed in children with choledochal cysts and spontaneous biliary perforation. Cannulation of the ampulla failed in 3 patients, of whom 1 had BA, 1 a choledochal stone, and 1 bile plug syndrome. Only 1 therapeutic ERCP was performed in a child with a stone completely obstructing the ampulla. The only complications were 1 asymptomatic case of hyperamylasemia and 1 of mild cholangitis successfully treated with antibiotics.ERCP is feasible and safe in the workup of neonatal cholestasis where other imaging modalities are inconclusive. Despite the expanding role of magnetic resonance cholangiography, ERCP may still have a role in the multidisciplinary workup of these patients.

Background In Norway, liver transplantation has been the treatment of choice for irreversible acute and chronic liver failure for 25 years. The aim of this article is to present a summary of the results obtained. Material and methods All liver transplants performed in Norway in the period 25.02.84-31.12.08 have been reviewed retrospectively with respect to patient and donor epidemiology, survival and recurrence. Results 651 transplants have been performed in this period. The annual number of transplants increased gradually up to the year 2000 (31), and more steeply afterwards - to 79 in 2008. Also the number of organ donations has increased and reached 98 (20 pr. million inh.) in 2008. 5-year patient survival was 53 % in the period 1984-1994. In the period 2001-2008, 1-year survival was 90 % and 5-year survival was 83 %. Interpretation The gradual improvement of results should be interpreted in light of improvements within transplant surgery, medicine and anaesthesiology and the increased local experience due to the increasing number of transplants performed. The transplant centre at Rikshospitalet has developed into being among the largest of its kind within the Nordic Countries and the results compare well with the best international data.

OBJECTIVES Although reduced cognitive function has been demonstrated after liver transplantation in children, few data are available concerning motor competence. METHODS Thirty-five children ages 4 to 12 years were tested using Movement Assessment Battery for Children (M-ABC) test at a median of 5.1 (3.9-6.9) years after liver transplantation and compared with reference material of healthy children. RESULTS Children with transplantation had worse M-ABC score 8.0 (interquartile range 5.0-11.5), compared with healthy children 3.5 (1.0-6.0) (P < 0.0001). All of the subscores (manual dexterity [P < 0.0001], ball skills [P = 0.0037], and balance [P = 0.0032]) were significantly worse in the children with liver transplantation compared with the healthy reference group. Twenty-nine percent of the children with liver transplantation had impaired motor competence, compared with 9% of a healthy reference group. Seventeen of the patients with transplantation were retested 1 year later, and 11 were tested 4 years later with no changes in total M-ABC score. Ball skill competence was worse 4 years after first assessment (P = 0.013). For children with transplantation and cholestatic liver disease (n =26), renal function was a significant predictor for total M-ABC score (P = 0.018). CONCLUSIONS Children with liver transplantation had impaired motor competence compared with healthy children. Ball skills developed adversely several years after liver transplantation, and motor competence did not improve with time after transplantation. Renal function was a significant predictor for motor competence in children with liver transplantation and cholestatic liver disease.

The aim of the present study was to assess whether the complication rate after ultrasound-guided percutaneous liver biopsies in children is affected by how frequently the procedure is performed by the operator.Medical charts and ultrasound descriptions of 311 ultrasound-guided percutaneous liver biopsy procedures performed by 18 radiologists at a single center from 2000 to 2011 were reviewed. Postbiopsy ultrasound the following day was performed after 97% of the procedures.There were no differences in the procedure-associated rate of major bleeding incidents (2.2% vs 0.8%, P = 0.38), minor bleeding incidents (15.2% vs 10.2%, P = 0.31), or abdominal pain (13.0% vs 10.6%, P = 0.61) among operators who performed ≤10 procedures and those who performed10 procedures during the study period. A higher rate of minor bleeding incidents were recorded after liver biopsy when operators had performed10 biopsies compared with operators who had performed20 pediatric liver biopsies during the study period (odds ratio 3.4 [1.3-9.1], P = 0.02). No association between the number of biopsies performed by the operator during the 2 years preceding the date of the biopsy and complications was found.Major complications are infrequent after pediatric liver biopsies and no relation between operator experience and major complications was found. We found a significant, but minor, effect of operator procedure frequency on the rate of minor bleeding incidents after ultrasound-guided pediatric liver biopsies.

Ischemic vascular complications and rejection occur more frequently with pediatric liver transplants versus adult liver transplants. Using intrahepatic microdialysis catheters, we measured lactate, pyruvate, glucose, and glycerol values at the bedside for a median of 10 days in 20 pediatric liver grafts. Ischemia (n = 6), which was defined as a lactate level3.0 mM and a lactate/pyruvate ratio20, was detected without a measurable time delay with 100% sensitivity and 86% specificity. Rejection (n = 8), which was defined as a lactate level2.0 mM and a lactate/pyruvate ratio20 lasting for 6 or more hours, was detected with 88% sensitivity and 45% specificity. With additional clinical criteria, the specificity was 83% without a decrease in the sensitivity. Rejection was detected at a median of 4 days (range = 1-7 days) before alanine aminotransferase increased (n = 5, P = 0.11), at a median of 4 days (range = 2-9 days) before total bilirubin increased 25% or more (n = 7, P = 0.04), and at a median of 6 days (range = 4-11 days) before biopsy was performed (n = 8, P = 0.05). In conclusion, microdialysis catheters can be used to detect episodes of ischemia and rejection before current standard methods in pediatric liver transplants with clinically acceptable levels of sensitivity and specificity. The catheters were well tolerated by the children, and no major complications related to the catheters were observed.

This study was performed to explore whether lactate, pyruvate, glucose, and glycerol levels sampled via microdialysis catheters in the transplanted liver could be used to detect ischemia and/or rejection. The metabolites were measured at the bedside every 1 to 2 hours after the operation for a median of 10 days. Twelve grafts with biopsy-proven rejection and 9 grafts with ischemia were compared to a reference group of 39 grafts with uneventful courses. The median lactate level was significantly higher in both the ischemia group [5.8 mM (interquartile range = 4.0-11.1 mM)] and the rejection group [2.1 mM (interquartile range = 1.9-2.4 mM)] versus the reference group [1.5 mM (interquartile range = 1.1-1.9 mM), P0.001 for both]. The median pyruvate level was significantly increased only in the rejection group [185 μM (interquartile range = 155-206 μM)] versus the reference group [124 μM (interquartile range = 102-150 μM), P0.001], whereas the median lactate/pyruvate ratio and the median glycerol level were increased only in the ischemia group [66.1 (interquartile range = 23.9-156.7) and 138 μM (interquartile range = 26-260 μM)] versus the reference group [11.8 (interquartile range = 10.6-13.6), P0.001, and 9 μM (interquartile range = 9-24 μM), P = 0.002]. Ischemia was detected with 100% sensitivity and greater than 90% specificity when a positive test was repeated after 1 hour. In 3 cases of hepatic artery thrombosis, ischemia was detected despite normal blood lactate levels. Consecutive pathological measurements for 6 hours were used to diagnose rejection with greater than 80% sensitivity and specificity at a median of 4 days before the activity of alanine aminotransferase, the concentration of bilirubin in serum, or both increased. In conclusion, bedside measurements of intrahepatic lactate and pyruvate levels were used to detect ischemia and rejection earlier than current standard methods could. Discrimination from an uneventful patient course was achieved. Consequently, intrahepatic graft monitoring with microdialysis may lead to the earlier initiation of graft-saving treatment.

In Norway, liver transplantation has been the treatment of choice for irreversible acute and chronic liver failure for 25 years. The aim of this article is to present a summary of the results obtained.All liver transplants performed in Norway in the period 25.02.84-31.12.08 have been reviewed retrospectively with respect to patient and donor epidemiology, survival and recurrence.651 transplants have been performed in this period. The annual number of transplants increased gradually up to the year 2000 (31), and more steeply afterwards - to 79 in 2008. Also the number of organ donations has increased and reached 98 (20 pr. million inh.) in 2008. 5-year patient survival was 53 % in the period 1984-1994. In the period 2001-2008, 1-year survival was 90 % and 5-year survival was 83 %.The gradual improvement of results should be interpreted in light of improvements within transplant surgery, medicine and anaesthesiology and the increased local experience due to the increasing number of transplants performed. The transplant centre at Rikshospitalet has developed into being among the largest of its kind within the Nordic Countries and the results compare well with the best international data.

Autoimmune mechanisms are involved in the pathogenesis of autoimmune hepatitis and primary sclerosing cholangitis. The disorders are rare but important to diagnose, as immunomodulating therapy can prevent liver failure. Cases of "overlap syndrome" between autoimmune hepatitis and primary sclerosing cholangitis are described.We have studied the medical records of children diagnosed with hepatitis and cholangitis treated at Rikshospitalet University Hospital from 1986 through 2004. Symptoms, findings and disease course are presented. A general overview is given of autoimmune hepatitis, primary sclerosing cholangitis and overlap syndrome in children.18 children were identified; 11 with autoimmune hepatitis, six with primary sclerosing cholangitis and one with overlap syndrome. Four of the children with primary sclerosing cholangitis had inflammatory bowel disease; two of them had ulcerative colitis and two had Crohn's disease. The patient with overlap syndrome had ulcerative colitis. Pathology was found in the liver biopsies of all the children. Sixteen patients were treated with prednisolone and azathioprine. Most of the children responded to immunomodulating therapy with normalization of liver function tests. Many relapsed while tapering steroids. None of the patients have needed a liver transplant.It is important to diagnose children with autoimmune liver disease, as children tend to respond well to immunomodulating therapy.

We report an 11-year-old boy with a slight developmental delay and epilepsy. After he was placed on valproate, he developed hepatic failure and increasing neurologic symptoms, including epilepsia partialis continua, and died. Autopsy findings in liver and cerebrum were consistent with progressive neuronal degeneration of childhood with liver disease, also called Alpers-Huttenlocher syndrome. Ragged red fibers and cytochrome c oxidase negative fibers were present in muscle. These results suggest that Alpers-Huttenlocher syndrome, at least in some patients, is a mitochondrial disease. (J Child Neurol 2000; 15:473-477).

The objective was to study whether the high erythropoietic stimulatory activity found in plasma from neonatal mice during the growth period is erythropoietin (Ep) alone, or Ep in combination with other factors. Plasma from hypertransfused neonatal (20 d) and adult (13-20 weeks) mice were compared with a radioimmunoassay (RIA) and a cell culture assay for Ep. The RIA determines immunoreactive Ep (iEp) while the cell culture assay reflects erythropoiesis stimulating factor(s) (ESF). Compared to control values, hypertransfusion resulting in PCVs of 55% and higher reduced the mean iEp levels in neonatal and adult mice by 82% and 38%, respectively (P less than 0.01). There was no detectable difference between the mean iEp levels of hypertransfused neonatal and adult animals (P greater than 0.3). The parallel ESF data showed a reduction in mean plasma ESF levels by 68% in hypertransfused neonatal and 72% in hypertransfused adult animals (P less than 0.001). And notably, in contrast to the iEp data, the mean ESF level found in hypertransfused neonatal mice with PCVs of 55% and higher was significantly above that of hypertransfused adult animals (P less than 0.001). No correlation was found between PCV and iEp (r less than 0.4, P greater than 0.1) or ESF (r less than 0.2, P greater than 0.2) in hypertransfused animals. The parallel data from the two Ep assays show that plasma from hypertransfused 20-d-old mice contain one or more erythropoietic stimulatory factors not detected by the RIA. It is concluded that part of the high erythropoietic stimulatory activity found in plasma from neonatal mice is due to non-Ep factors.

The erythropoietic activity and erythrocyte 2,3-diphosphoglycerate (2,3-DPG) were studied during and after the nadir of the post-natal anaemia in normal, rapidly growing rabbits, from the 12th to the 35th day after birth. Whole blood haemoglobin (Hb) decreased from 9.3 g dl-1 on the 12th to 4.9 g dl-1 on the 25th day, while erythropoiesis-stimulating factor(s) (ESF) in plasma (determined by a cell culture assay) concomitantly rose from undetectable to high levels. In spite of marked rise in body weight, from 250 to 480 g, estimated haemoglobin mass (Hb mass) and reticulocyte mass production rate (Rt prod) remained essentially the same, about 1.8 g and 0.3 ml day-1. From the 25th to the 35th day, ESF decreased to a lower level, while Hb increased to 10.8 g dl-1 and Hb mass and Rt prod rose sharply, to 6.9 and 1.2 ml day-1. The 2,3-DPG rose markedly during the observation period, but showed a transient decline on the 29th day, simultaneously with the peak in reticulocyte counts (Rt) (24%) and release of young erythrocytes with low 2,3-DPG. The data indicate that the regions governing the erythropoietin production/release became increasingly sensitive to hypoxia during the observation period. The possibility also exists that the increase in ESF was due only in part to hypoxic stimulation. It could be related to the maturation of the animal in other ways, such as shift from extra-renal to renal erythropoietin production and the growth. The lack of response to increasing stimulation indicates that the erythropoiesis was restricted by the availability of iron and/or other factors necessary for erythrocyte and haemoglobin production.

The postnatal anemia in rabbits is accompanied by a marked rise in the plasma erythropoiesis stimulating factor(s) (ESF). The purpose of this study was to establish whether the increase in plasma ESF is only related to the anemia, or whether other mechanisms also are involved. Two matched groups of rabbits were studied from the 15th to the 36th day after birth. One group received iron parenterally and had no postnatal fall in hemoglobin concentration (Hb), the other developed the usual anemia. In both groups plasma ESF was undetectable on the 15th day, and also on the 22nd day, despite a marked fall in Hb in the untreated group and rise in the iron-treated group. Thereafter plasma ESF showed a slight, continuous rise in the nonanemic rabbits, in contrast to a marked, transient rise with maximum on the 29th day in the untreated group. On the 36th day there was no difference between the groups. In the iron-treated group the reticulocyte production rate remained unchanged, while the Hb mass rose continuously. In the untreated animals there was an initial decline in reticulocyte production rate, while Hb mass showed a slight increase. From the 29th day, however, reticulocyte production rate rose to the same level as in the iron-treated group and Hb mass rose markedly. In conclusion, the rise in plasma ESF during the postnatal anemia in rabbits is only in part related to the low Hb. Hypoxia-independent mechanisms, probably related to the growth and maturation per se also are involved. The lack of erythropoietic response to the rise in plasma ESF is due to lack of available iron.

The erythropoiesis stimulating factor(s) (ESF) in plasma from 20-day-old WLO-mice have previously been studied by a cell culture assay, and also by means of gel filtration chromatography and affinity chromatography. It was concluded that the high levels of ESF found in the neonatal mouse plasma probably consisted of erythropoietin (Ep) alone. The objective of the present investigation was to obtain further information of whether this high ESF found in vitro is Ep alone, or Ep in combination with other factors. To accomplish this plasma from 20-day-old WLO mice and a standard Ep were studied in vivo by the exhypoxic polycythaemic mice assay for Ep, with and without preincubation with rabbit anti-Ep serum (AS). Aliquots of some samples were also studied in vitro by the exhypoxic polycythaemic mice assay for Ep, with and without pre- in both assays (P less than 0.001). However, incubation with AS significantly reduced (P less than 0.001) but did not totally block either the in vivo or the in vitro activity of the plasma (P less than 0.005). This also was the case regarding the in vivo activity of the standard Ep (P less than 0.001), while the in vitro activity of this Ep preparation was totally blocked by incubation with AS (P greater than 0.3). These results indicate that a considerable part of the high erythropoietic stimulatory activity found in plasma from 20-day-old mice, with both assays, is Ep. This supports the previous in vitro studies. However, the present results also support the conclusion that part of the activity is due to non-Ep stimulatory factors.

During the early neonatal period of rapid growth in the mouse, increased plasma levels of erythropoiesis stimulating factor(s) (ESF) have been found when measured by an in-vitro bioassay technique. It is unclear whether these increased ESF levels represent increased levels of circulating erythropoietin (Ep) alone or Ep in combination with other less-defined erythropoietic stimulatory factors. To examine this issue, plasma from neonatal mice of varying post-natal ages and from normoxic and hypoxic adult mice was studied. We found that plasma Ep levels measured by radioimmunoassay (RIA) correlated significantly with in-vitro bioassayed ESF levels (r = 0.84, P less than 0.0001, n = 21). Although an in-vivo bioassay for plasma Ep proved too insensitive for rigorous correlation with data from the RIA and in-vitro bioassay, the in-vivo data were in qualitative agreement with the other two, more sensitive, assays. In all three assays the highest plasma levels were observed in the 20-day-old mice and in adult mice which had been subjected to hypobaric hypoxia for 8 h. Based on the strong agreement of the results obtained with the RIA and the in-vitro bioassay in both neonatal and adult mouse plasma, we conclude that the high plasma ESF levels of 20-day-old mice measured with the in-vitro bioassay are largely immunochemically identifiable Ep. However, the data also suggest the presence of non-Ep factors in neonatal plasma which stimulate the in-vitro bioassay.

High levels of plasma erythropoiesis stimulating factor(s) (ESF) have been found in neonatal WLO-mice during the period of rapid growth. If the high ESF activity is due to the concomitant physiological anaemia of infancy alone, it should be possible to block erythropoiesis by hypertransfusion. Mice were hypertransfused starting on day 14, and killed on day 20. Although hypertransfusion reduced the ESF levels by approximately 55% (P less than 0.001), ESF levels were still detectable in the cell culture assay used (P less than 0.001). Moreover, hypertransfused mice showed active erythropoiesis in the bone marrow, and none had a reticulocyte count below 2%. No correlation was found between PCV and ESF in the hypertransfused animals (r = 0.07, P greater than 0.5), nor was there any difference in weight gain between control and hypertransfused mice (P greater than 0.5). These results show that hypertransfusion did not totally supress erythropoiesis in neonatal WLO-mice, which is different from hypertransfused adult mice. The data indicate that the high plasma ESF found in neonatal WLO-mice during the growth period are not due to the anaemia alone. These findings support studies indicating that regulation of erythropoiesis in the neonate differs from the adult. Factors related to growth per se could be responsible for this difference.

High levels of plasma erythropoiesis stimulating factor(s) (ESF) have been found in neonatal WLO-mice during rapid growth. A previous study on hypertransfused neonatal animals indicated that the high ESF could not be due to the concomitant postnatal anemia alone. The present investigation was performed to answer the question: Is the high plasma ESF in neonatal WLO-mice erythropoietin (Ep) alone, or Ep in combination with other factors? The ESF of plasma from 20-day-old animals and standard Ep were compared in a cell culture assay for ESF based on erythroid colony formation, and also by means of gel filtration chromatography and affinity chromatography. Nonfractionated plasma and standard Ep showed parallel dose response curves and additive activity in the ESF assay. After gel filtration the detectable ESF of plasma was eluted in the same position as that of standard Ep, corresponding to an estimated molecular weight range of 34-65,000 daltons. The ESF of intact plasma, fractionated plasma, and standard Ep were identically bound to and eluted from the affinity chromatography column. These results show that the ESF of plasma from 20-day-old animals can neither be separated into several factors, nor distinguished from that of standard Ep by the methods used. It is therefore concluded that the high plasma ESF found in neonatal WLO-mice probably consists of Ep alone.

Since hematocrit is one of the main determinants of blood viscosity, the regulation of erythrocyte production is important in maintaining nomral blood viscosity. Hemoglobin/hematocrit, erythropoiesis stimulating factors,ESF, 2.3.DPG and P50% were studied in preterm infants, rabbits, rats and mice. Only the human newborn has postnatal polyglobulia, the other species had hematocrit similar to the adult levels. Following birth hb/hct drop in almost all mammals reaching the nadir at the time of weaning. In the human the nadir is unrelated to this event. The development of the anemia occurs when the animals are growing rapidly and in rabbits there is a correlation between degree of anemia and weight gain. The anemia does not hamper growth rate. At the nadir ESF is increased in the species studied and there is a correlation between the concentration of ESF and weight gain. In rabbits 2.3.DPG increases following birth and the available oxygen does not change during the development of the anemia. Thus the low hb cone. does not reduce the oxygenation of the tissues to a degree which give marked changes. The early anemia is iron respon sive in most species studied, suggesting that it may be re lated to environmental causes. The early anemia of prematurity is not alleviated by peroral iron. The rapid changes in hematocrit observed following birth must be taken into consideration in all hemorheological studies.