Anti-activated factor II assay for monitoring unfractionated heparin in children: results of the HEARTCAT study.

Essentials Unfractionated heparin has variable effects in children and therefore, monitoring is essential. A randomized controlled trial substudy investigating an anti-IIa assay in children was conducted. Anti-IIa values are lower in younger children, an effect more pronounced at low-dose heparin. Heparin effect on Xa and IIa is not equal, particularly in infants and after high-dose heparin. SUMMARY: Background Unfractionated heparin (UFH) is used for the prophylaxis and treatment of thrombosis in children. Laboratory monitoring of UFH is needed to prevent over-anticoagulation or under-anticoagulation. Objectives To investigate the association between UFH dose and UFH effect as monitored with the anti-activated factor II (FIIa) assay, the relationship between anti-FIIa and anti-activated factor X (FXa) effects, and the influence of patient age and other factors on UFH effect. Patients and methods This was a randomized controlled trial in children during cardiac catheterization, comparing high-dose UFH (100 units kg-1 bolus) with low-dose UFH (50 units kg-1 bolus). Blood samples were drawn at baseline, and after 30 min, 60 min, and 90 min. For the purpose of this study, 49 children and 117 blood samples were evaluated. Results The anti-FIIa assay discriminated well between high-dose and low-dose UFH. Multiple regression demonstrated significant influences of UFH dose and age on anti-FIIa levels. Younger children had lower anti-FIIa levels than older children, an effect that was more pronounced with low-dose UFH. Anti-FXa/anti-FIIa ratios were equal with low-dose UFH. However, anti-FXa levels were relatively increased over anti-FIIa levels in infants and after high-dose UFH bolus administration. Conclusion The UFH effect on anti-FIIa levels is lower in infants than in older children. This influence of age appears to be dose-dependent, being more pronounced with low-dose UFH. Anti-FXa and anti-FIIa levels are not equal, particularly in infants and after high-dose UFH. Monitoring UFH solely with anti-FXa assays may not be sufficient in children, and the anti-FIIa assay may provide important complementary information.

Prenatal diagnosis of giant cardiac rhabdomyoma in tuberous sclerosis complex: a new therapeutic option with everolimus.

Tuberous sclerosis complex (TSC) is a genetic disorder characterized by abnormal cell proliferation and tumor growth in a number of organ systems, primarily the brain, kidneys, eyes and heart. Clinical symptoms vary according to the location of the tumor. The most common disorders are seizures, neurodevelopmental disorders, renal failure and arrhythmias. TSC was found to be influenced by inhibitors of the protein kinase mammalian target of rapamycin (mTOR), which regulates abnormal cellular proliferation. mTOR inhibitors have been studied effectively in patients with subependymal giant-cell astrocytomas and renal angiolipomas in the context of TSC. We describe a prenatally diagnosed case of giant rhabdomyoma, due to right ventricular outflow tract obstruction, which presented as a duct-dependent lesion. Postnatal treatment with the mTOR inhibitor everolimus initiated significant regression of the cardiac tumor. This finding suggests that mTOR inhibitor therapy is an option for giant rhabdomyomas that develop in the neonatal period.

Incidence of thrombotic and bleeding complications during cardiac catheterization in children: comparison of high-dose vs. low-dose heparin protocols.

BACKGROUND: During cardiac catheterization (CC) in children, unfractionated heparin (UFH) is used for primary prophylaxis of thrombotic events (TE). However, the optimal UFH dose to minimize TE and bleeding in children has yet to be established. OBJECTIVES: To (i) objectively assess the incidence of TE and bleeding during pediatric CC using clinical assessment and ultrasound; and (ii) compare a high-dose vs. low-dose UFH protocol for thromboprophylaxis. METHODS: A randomized controlled trial (RCT) comparing high-dose UFH (100 units kg(-1) bolus, followed by 20 units kg h(-1) continuous infusion) vs. low-dose UFH (50 units kg(-1) bolus) during CC. Outcome assessment was by clinical examination and vascular ultrasound, performed by blinded examiners before and within 48 h after CC. Children with no consent for randomization were followed in a cohort receiving standard-of-care UFH (parallel-cohort RCT). RESULTS: A total of 227 children were included; 137 were randomized and 90 followed in the cohort study. The overall incidence of TE was 4.6% and bleeding 6.6%. The RCT was stopped early for futility as there were no differences between the high-dose and the low-dose UFH in TE (5% vs. 3%; risk ratios [RR] 1.5, 95% confidence interval [CI] 0.3; 9) and bleeding (7% vs. 12%, RR 0.6, 95% CI 0.2; 2). There were also no differences when RCT and cohort study populations were combined. CONCLUSIONS: The incidences of TE and bleeding during CC in children were low. There were no differences between the high-dose and the low-dose UFH protocols studied. Although Heparin Anticoagulation Randomized Trial in Cardiac Catheterization (HEARTCAT) was not designed as non-inferiority trial, low-dose UFH (50 units kg(-1) bolus) appears sufficient for thromboprophylaxis during CC.

Balloon valvuloplasty in the treatment of congenital aortic valve stenosis--a retrospective multicenter survey of more than 1000 patients.

BACKGROUND: The value of balloon valvuloplasty of the aortic valve in childhood is still under debate. OBJECTIVE: To evaluate the results of the procedure in a retrospective multicenter survey of a large cohort over a long time interval. METHODS: Retrospective analysis of 1004 patients with balloon valvuloplasty of the aortic valve performed between 9/1985 and 10/2006 at 20 centers in Germany, Austria and Switzerland. Amongst others, the following parameters were evaluated before and after the procedure as well as at the end of follow-up or before surgery: clinical status, left ventricular function, transaortic pressure gradient, degree of aortic regurgitation, freedom from re-intervention or surgery. PATIENTS: Patients from 1 day to 18 years of age with aortic valve stenosis were divided into four groups: 334 newborns (1-28 days); 249 infants (29-365 days); 211 children (1-10 years), and 210 adolescents (10-18 years). RESULTS: Median follow-up was 32 months (0 days to 17.5 years). After dilatation the pressure gradient decreased from 65 (± 24)mm Hg to 26 (± 16)mm Hg and remained stable during follow-up. The newborns were the most affected patients. Approximately 60% of them had clinical symptoms and impaired left ventricular function before intervention. Complication rate was 15% in newborns, 11% in infants and 6% in older children. Independently of age, 50% of all patients were free from surgery 10 years after intervention. CONCLUSIONS: In this retrospective multicenter study, balloon valvuloplasty of the aortic valve has effectively postponed the need for surgery in infants, children and adolescents up to 18 years of age.

Simultaneous optical and electrical recording of single gramicidin channels.

We report here an approach for simultaneous fluorescence imaging and electrical recording of single ion channels in planar bilayer membranes. As a test case, fluorescently labeled (Cy3 and Cy5) gramicidin derivatives were imaged at the single-molecule level using far-field illumination and cooled CCD camera detection. Gramicidin monomers were observed to diffuse in the plane of the membrane with a diffusion coefficient of 3.3 x 10(-8) cm(2)s(-1). Simultaneous electrical recording detected gramicidin homodimer (Cy3/Cy3, Cy5/Cy5) and heterodimer (Cy3/Cy5) channels. Heterodimer formation was observed optically by the appearance of a fluorescence resonance energy transfer (FRET) signal (irradiation of Cy3, detection of Cy5). The number of FRET signals was significantly smaller than the number of Cy3 signals (Cy3 monomers plus Cy3 homodimers) as expected. The number of FRET signals increased with increasing channel activity. In numerous cases the appearance of a FRET signal was observed to correlate with a channel opening event detected electrically. The heterodimers also diffused in the plane of the membrane with a diffusion coefficient of 3.0 x 10(-8) cm(2)s(-1). These experiments demonstrate the feasibility of simultaneous optical and electrical detection of structural changes in single ion channels as well as suggesting strategies for improving the reliability of such measurements.

Intra-arterial thrombolysis for the treatment of perioperative childhood cardioembolic stroke.

Local intra-arterial lysis using recombinant tissue plasminogen activator (rTPA) was performed in a 6 and 2/3-year-old patient with major cardioembolic ischemic stroke 48 hours after intracardiac surgery. Selective application of 2.5 mg rTPA (0.11 mg/kg body weight) resulted in recanalization of the occluded cerebral vasculature with good neurologic recovery.

Impaired brain glucose metabolism in patients with Down syndrome.

A series of impaired metabolic functions in Down Syndrome (DS) including glucose handling has been described. Recent information from positron emission tomography studies in DS patients and our finding of downregulated phosphoglucose isomerase (PGI) in fetal brain with DS by gene hunting using subtractive hybridization, made us investigate PGI, a key enzyme of glucose metabolism, in brain of patients with DS, Alzheimer's disease (AD) and controls. PGI and phosphofructokinase (PFK) activities were determined in frontal, parietal, temporal, occipital lobe and cerebellum of 9 controls, 9 patients with DS and 9 patients with AD. PGI activity in DS brain was significantly decreased in frontal, temporal lobe and cerebellum, comparable to controls in parietal lobe and elevated in occipital lobe. Brain PGI activity of patients with AD was comparable to controls in all regions tested, PFK, a rate limiting enzyme of glucose metabolism, was comparable between all brain regions of all three groups. Data of this study confirm impaired glucose metabolism in DS proposed in literature and found by positron emission tomography (PET) studies. We show that changes in glucose handling in patients with AD as evaluated by PET studies are not supported by our data, although not contradictory, as determinants other than glucose metabolizing enzymes as e.g. vascular factors and glucose transport may account for these findings. Changes of downregulated PGI found by subtractive hybridization at the transcriptional level in fetal DS brain along with our findings in DS brain regions suggest a strong specific link between glucose metabolism and DS rather than AD.

Superselective Intra-arterial Thrombolysis for Acute Cardioembolic Stroke in a Child with Idiopathic Dilated Cardiomyopathy. A Case Report.

SUMMARY: We describe a case of cardioembolic dominant hemisphere internal carotid artery occlusion in a child with idiopathic dilated cardiomyopathy. The patient was subjected to superselective local intra-arterial thrombolysis using recombinant tissue plasminogen activator (A lteplase; Actilyse((R))). In presence of good collateral flow local intra-arterial thrombolysis prevented a major dominant hemisphere ischaemic stroke, although post-interventional computed tomographic scans disclosed haemorrhagic conversion in the left corpus striatum. Forty eight months after ischaemic stroke and thrombolysis the patient is ambulatory with a moderate neurologic deficit.

Decreased transcription factor junD in brains of patients with Down syndrome.

JunD is a member of the Jun family of transcription factors (TF), recently shown to negatively regulate cell growth and antagonizes transformation by the protooncogene ras: c-jun decreases while junD is accumulating when fibroblasts become quiescent. Furthermore, overexpression of junD resulted in slower growth and an increase in cells in G0/G1. Performing gene hunting on fetal Down syndrome (DS) brain we found a sequence downregulated and homologous to junD. This observation made us examine junD protein levels in adult brain specimens. Western blot experiments were carried out in five brain regions of aged patients with DS (n = 9), controls (n = 9) and patients with Alzheimer's disease (AD, n = 9). We found that junD in AD brains were comparable to controls, whereas junD levels were significantly and remarkably reduced in frontal, temporal lobe and cerebellum of patients with DS. These findings may indicate a specific finding in DS and were not linked to the AD-like-neuropathological changes of plaques and tangles, observed in DS from the fourth decade, which is also suggested by the findings of downregulated junD at the mRNA level revealed by the gene hunting technique (subtractive hybridization) in fetal DS brain. We propose that junD plays a role for the impaired development and wiring of DS brain, maybe already early in life.

Transcription of the XRCC1 gene in kidneys of radiosensitive and radioresistant mice following whole-body irradiation.

The XRCC1 gene was described to play a role in the sensitivity of mammalian cell lines towards ionizing irradiation. Cells with a mutation of this gene present with decreased single-strand break repair and reduced recombination repair, show increased double-strand breaks, and the sister chromatid exchange is increased up to tenfold. The goal of our study was to investigate the transcription of this gene in the kidney following ionizing irradiation in the mouse, as this could be relevant to the pathogenetic mechanisms found in radiation nephropathy. Furthermore, we intended to examine whether radiation-sensitive mice would show a transcriptional pattern different from radiation-resistant mice. Radiation-sensitive BALB/c/J/Him mice and radiation-resistant C3H/He/Him mice were whole body irradiated with X-ray at 2, 4, and 6 Gy and sacrificed 5, 15, and 30 min after irradiation. mRNA was isolated from kidney cortex and hybridized with probes for XRCC1 and beta-actin as a housekeeping gene control. Following irradiation at 2 Gy, radiation-resistant mice increased transcriptional levels of mRNA-XRCC1/mRNA-beta-actin as early as after 5 min, and 15 and 30 min after irradiation, XRCC1 transcription was still higher than in radiation-sensitive mice. At higher radiation doses, no differences were found. This finding is the first in vivo study on XRCC1 of this kind and may in part explain the differences in the radiation sensitivity between the two strains studied.

Deficient transcription of subunit RPA 40 of RNA polymerase I and III in heart of rats with neonatal asphyxia.

RNA polymerases transcribe nuclear genes for ribosomal RNA thus representing ribosomal biogenesis. RNA polymerase I transcribes class I genes, coding for large ribosomal RNA and is located in the nucleolus. RNA polymerase III transcribes class III genes, those that encode a number of small ribosomal RNA molecules. Both RNA polymerases form ribosomal biogenesis in a concerted action and have a common subunit, RPA40, essential for function and integrity. The aim of our study was to study the influence of hypoxia/asphyxia on transcription of this subunit as deterioration of ribosomal biogenesis may not be compatible with life. To test this hypothesis we used a nonsophisticated model of neonatal asphyxia. Rat pups were exposed to various asphyctic periods up to twenty minutes and heart tissue was taken for the evaluation of mRNA RPA40 levels, pH measurements and histological evaluation of the nucleolus by silver staining. mRNA RPA40 levels gradually decreased with the length of the asphyctic period paralleling the decrease of pH. Silver staining was remarkably decreased at the asphyctic period of 20 minutes. Our findings of decreased transcription of this essential RNA polymerase subunit indicate impairment of the ribosomal RNA synthetizing machinery and the histological findings suggest its structural relevance. This is the first in vivo observation of deteriorated RNA polymerase in asphyxia/hypoxia.

[Chronic peritoneal dialysis as home therapy in childhood--risks and complications]. / Chronische Peritonealdialyse als Heimtherapie im Kindesalter--Risiken und Komplikationen.

BACKGROUND: The aim of our study was to ascertain the complications of chronic peritoneal home dialysis in childhood. PATIENTS: 17 children were treated by ambulatory peritoneal home dialysis between 1984 and 1994 at the paediatric dialysis unit of the University Children's Hospital in Vienna, Austria. Their average age was 6.5 years (1 week to 12 years); 7 (41.2%) children were below school age (< 6 years). RESULTS: In our observation period of 369 dialysis months (DM), the average duration of dialysis was 21.7 months (4.0-74.3). In relation to total DM the incidence of peritonitis was 1:23.1 of exit site infection 1:14.8 and of catheter related complications 1:41.0. 5 children developed hernias. 5 children were switched to haemodialysis and 8 children received kidney transplants. 2 children died from non-dialysis-associated causes. CONCLUSION: Peritoneal dialysis, in contrast to haemodialysis, is a home treatment modality applicable even to infants. The most common complication is infection. Our data and the European and North American literature show that by close ambulatory monitoring and special hygenic procedures peritonitis frequency can be markedly reduced.

Similar deficits of central histaminergic system in patients with Down syndrome and Alzheimer disease.

In order to study whether Alzheimer-like neuropathological changes involve the central histaminergic system we measured the concentration of histamine, its precursor histidine as well as the activity of histidine decarboxylase (HDC) and histamine-N-methyl-transferase (HMT) in frontal cortex of aging Down syndrome (DS) patients, Alzheimer patients and control individuals. The study populations were also investigated for choline acetyltransferase (ChAT) activity, since reduced ChAT activity is an established biochemical hallmark in DS and Alzheimer disease (AD). HDC and ChAT activity were reduced in brains of both DS and Alzheimer patients versus control patients. Additionally, we observed a significant decrease of histamine levels in the DS group. Histamine levels in AD brains tended to be decreased. Histidine concentrations and HMT activities were comparable between the three groups. Thus, our results for the first time show histaminergic deficits in brains of patients with DS resembling the neurochemical pattern in AD. Neuropathological changes may be responsible for similar neurochemical alterations of the histaminergic system in both dementing disorders.

Arginine reduces kidney collagen accumulation, cross-linking, lipid peroxidation, glycoxidation, kidney weight and albuminuria in the diabetic kk mouse.

In diabetic nephropathy a major current concept for pathogenesis is increased collagen accumulation in the glomerulus by increased collagen synthesis and decreased degradation. In the present study, we tested the hypothesis whether arginine is able to influence kidney lipid peroxidation, glycoxidation, collagen accumulation, glucose-mediated cross-linking, hydroxy radical attack, protein oxidation, nitric oxide formation and albuminuria in the diabetic kk mouse. Ten diabetic kk mice were given arginine 50 mg/kg body weight, 10 diabetic kk mice were not treated and used as negative controls and 10 kk mice were kept as healthy controls. Our results show that oral administration of low-dose arginine reduces kidney collagen accumulation as reflected by kidney hydroxyproline, cross-linking as reflected by pentosidine, lipid peroxidation, glycoxidation as reflected by carboxymethyl lysine, kidney weight and albuminuria in the diabetic kk mouse. Albuminuria in untreated animals was closely correlated with lipid peroxidation. Our results in the spontaneously diabetic kk mouse representing type 2 diabetes mellitus therefore confirm and extend recent findings of collagen reduction by arginine in a different animal model. The mechanism of reducing proteinuria can be assigned to the blocking of lipid peroxidation products by L-arginine.

Distribution and disappearance of the radiolabeled carbon derived from L-arginine and taurine in the mouse.

L-arginine and taurine are still in the center of physiological and pharmacological research. Although the fate of nitrogen of both compounds and of the 35S-taurine is well-documented, the fate of the carbon skeleton has not been elucidated yet. We studied the organ distribution of 14C arginine and 14C taurine over time in the mouse using whole body autoradiography with densitometric image analysis. We describe different organ distribution patterns. Kidney, heart, lung, the Harderian gland, the central nervous system, intestine and testis showed a comparable pattern of arginine disappearance in contrast to rapid disappearance in the salivary gland and the accumulation pattern in bone and spleen. Data on 14C taurine of liver, kidneys, lung, testis and Harderian gland resembled the arginine pattern; Accumulation of taurine carbon was found in salivary gland, bone, intestine, heart and brain. Our studies challenge and demand further related studies to obtaining more information on the fate of the carbon skeleton of these amino acids.

L-Arginine reduces lipid peroxidation in patients with diabetes mellitus.

A current concept for the development of diabetic long-term complications is the involvement of oxidative stress, as, e.g., lipid peroxidation, in the diabetic state. Data published recently show also oxidative damage to DNA, which might be one factor for accelerated aging and diabetic microangiopathy. In our study we tested the hypothesis that L-arginine can reduce lipid peroxidation in patients with diabetes. We performed a blind placebo controlled study with crossing over two treatment periods for 3 months. Thirty patients with diabetes mellitus were randomly assigned to treatment group A (first treatment then placebo) and B (first placebo then treatment). Treatment consisted of two daily dosages of 1 g L-arginine free base. Lipid peroxidation as reflected by malondialdehyde was evaluated in urine using a standard HPLC assay. After 3 months of treatment there was a significant reduction in malondialdehyde levels in group A (p < .0032), whereas there was no difference compared to the baseline values after three months of placebo treatment in group B (p < .97). After crossing over, there was a significant reduction in malondialdehyde levels in group B (p < .0002). Group A showed a significant increase in malondialdehyde levels (p < .0063) returning to baseline values. L-Arginine treatment was able to reduce the lipid peroxidation product malondialdehyde. This provides evidence that treatment with L-arginine may counteract lipid peroxidation and thus reduce microangiopathic long-term complications in diabetes mellitus.

Use of prostaglandin I2 in three small children at high risk of early renal graft thrombosis.

We report the use of prostaglandin I.2. (PGI2) in three small children weighing less than 15 kg at high risk of graft thrombosis after cadaveric renal transplantation complicated by acute tubular necrosis. PGI2 was started at a dose of 5 ng/kg per min within the first 6 h after transplantation, and was continued for 12-15 days. Before and during PGI2 infusion, color-coded and pulsed Doppler sonography was performed. We found immediate restoration of diastolic flow, consistent with a decrease in vascular resistance. During the subsequent days, the sonographically assessed flow pattern and clinical graft function improved gradually. None of the three consecutively treated children developed graft thrombosis or lost his graft; no clinically relevant bleeding or adverse hemodynamic or pulmonary effects were seen.

Estimation of total creatinine clearance is unreliable in children on peritoneal dialysis.

OBJECTIVE: To test the reliability of creatinine clearance in children on peritoneal dialysis (PD). DESIGN: Longitudinal, case-controlled. SETTING: Routine clinic visits at the pediatric dialysis unit of the Universitätskinderklinik of Vienna. PATIENTS: Eleven children (2-13 years, 10-55 kg) with end-stage renal disease on PD. INTERVENTIONS: Creatinine clearance (CCr) was determined by measuring creatinine excretion (ECr) over 24 hours in both dialysate and urine. Each child had three to five separate measurements of their CCr. At the same time we also calculated the Schwartz formula clearance from the patient's height and serum creatinine, using a modified correlate. MAIN OUTCOME MEASURES: Reliability of CCr was assessed by two approaches. First, we compared each serial measurement with the mean value for each patient and thereby assessed the "intramethodical" variability. Second, we compared each CCr with the simultaneous formula clearance and assessed the "intermethodical" disagreement. RESULTS: Twenty-seven percent of the measurements of CCr were classified as unreliable based on a comparison with the mean value for each patient. Reliability was closely correlated with residual renal function (p < 0.01); only 12% of the measurements in the anuric patients were classified as unreliable (vs 31% in the patients with residual renal function). The simultaneous formula clearance was less variable than the CCr. The formula clearance had a sensitivity of 93% and a specificity of 60% for detecting unreliable values of CCr. CONCLUSION: Estimation of total CCr is unreliable in pediatric patients on PD. A simultaneous formula clearance can be used to detect which values are unreliable.