Paediatric heart transplantation: life-saving but not yet a cure

In the 1980s, heart transplantation was the first successful treatment for infants born with hypoplastic left heart syndrome. Infants who have required heart transplantation benefit from immunologic "advantages," including long-term survival free from cardiac allograft vasculopathy. Currently ∼ 90% of children undergoing a heart transplant are reaching their first-year anniversary and the clinical practices of paediatric heart transplantation have dramatically improved. These successes are largely attributed to research sponsored by the Pediatric Heart Transplant Study Group, the International Society of Heart and Lung Transplantation and, more recently, the Non-profits Enduring Hearts and Additional Ventures. Despite these successes, the field is challenged to increase progress to achieve long-term survival into adulthood. The wait-list mortality, especially among infants, is unacceptably high often leading to palliative measures that can increase post-transplant mortality. Cardiac allograft vasculopathy remains a major cause for progressive graft loss of function and sudden death. The relative tolerance seen in immature recipients has not been translated to modifying older recipients' post-transplant outcomes. The modifiable cause(s) for the increased risks of transplantation in children of different ethnicities and races require definition. Addressing these challenges faces the reality that for-profit research favours funding adult recipients, with ∼ 10-fold greater numbers, and their more modest longevity goals. Advocacy for funding "incentives" such as the Orphan Drug rules in the United States and upholding principles of equity and inclusion are critical to addressing the challenges of paediatric heart transplant recipients worldwide.

Heart Transplantation in Children With Down Syndrome

Background

Children with Down syndrome (DS) have a high risk of cardiac disease that may prompt consideration for heart transplantation (HTx). However, transplantation in patients with DS is rarely reported. This project aimed to collect and describe waitlist and post– HTx outcomes in children with DS.

Methods and Results

This is a retrospective case series of children with DS listed for HTx. Pediatric HTx centers were identified by their participation in 2 international registries with centers reporting HTx in a patient with DS providing detailed demographic, medical, surgical, and posttransplant outcome data for analysis. A total of 26 patients with DS were listed for HTx from 1992 to 2020 (median age, 8.5 years; 46% male). High‐risk or failed repair of congenital heart disease was the most common indication for transplant (N=18, 69%). A total of 23 (88%) patients survived to transplant. All transplanted patients survived to hospital discharge with a median posttransplant length of stay of 22 days. At a median posttransplant follow‐up of 2.8 years, 20 (87%) patients were alive, 2 (9%) developed posttransplant lymphoproliferative disorder, and 8 (35%) were hospitalized for infection within the first year. Waitlist and posttransplant outcomes were similar in patients with and without DS (P=non‐significant for all).

Conclusions

Waitlist and post‐HTx outcomes in children with DS selected for transplant listing are comparable to pediatric HTx recipients overall. Given acceptable outcomes, the presence of DS alone should not be considered an absolute contraindication to HTx.

Heterogeneous outcomes of liver disease after heart transplantation for a failed Fontan procedure

BACKGROUND

Fontan-associated liver disease (FALD) uniformly affects patients with long-term Fontan physiology. The effect of isolated heart transplant (HT) on the course of FALD post-HT is not well understood.

METHODS

We evaluated serial liver imaging pre- and post-HT to assess liver changes over time in a single-center retrospective analysis of Fontan HT recipients who had pre- and ≥1-year post-HT liver imaging. Available patient demographic and clinical data were reviewed, including available liver biopsy results.

RESULTS

Serial liver imaging was available in 19 patients with a median age at HT of 12 years (range 3-23), the median age from Fontan to HT of 5.7 years (range 0.8-16), and the median time from imaging to follow up of 27 months (range 12-136 months). Pre-HT liver imaging was classified as follows: normal (n=1), congested (n=9), fibrotic (n=7), and cirrhotic (n=2). The majority of transplanted patients (15/19) had improvement in their post-HT liver imaging, including 13 patients with initially abnormal imaging pre-HT having normal liver imaging at follow-up. One patient had persistent cirrhosis at 26-month follow-up, one patient had unchanged fibrosis at 18-month follow-up, and one patient progressed from fibrosis pre-HT to cirrhosis post-HT at 136 months. No patients had overt isolated liver failure during pre- or post-HT follow-up. Liver biopsy did not consistently correlate with imaging findings.

CONCLUSIONS

Post-HT liver imaging evaluation in Fontan patients reveals heterogeneous liver outcomes. These results not only provide evidence for the improvement of FALD post-HT but also show the need for serial liver imaging follow-up post-HT.

Association of low center performance evaluations and pediatric heart transplant center behavior in the United States

BACKGROUND

To date, no study has evaluated the effects of low center performance evaluations (CPE) on pediatric heart transplant center behavior. We sought to assess the impact of low CPE flags on pediatric heart transplant center listing and transplant volumes and center recipient and donor characteristics.

METHODS

We included centers performing at least 10 pediatric (age <18 years) transplants during the Scientific Registry of Transplant Recipients reporting period January 2009-June 2011 and evaluated consecutive biannual program specific reports until the last reporting period January 2016-June 2018. We evaluated changes in center behavior at following time points: a year before flagging, a year and two years after the flag; and at last reporting period.

RESULTS

During our study period, 24 pediatric centers were non-flagged and 6 were flagged. Compared to non-flagged centers, there was a decline in candidate listings in flagged centers at the last reporting period (mean increase of 5.5 ± 12.4 listings vs"?> mean decrease of 14.0 ± 14.9 listings; p = .003). Similarly, the number of transplants declined in flagged centers (mean increase of 2.6 ± 9.6 transplants vs"?> mean decrease of 10.0 ± 12.8 transplants; p = .012). Flagged centers had declines in listings for patients with restrictive cardiomyopathy, re-transplant, renal dysfunction, those on mechanical ventilation and extracorporeal membrane oxygenation. There was no significant change in donor characteristics between flagged and non-flagged centers.

CONCLUSIONS

Low CPE may have unintended negative consequences on center behavior leading to declines in listing and transplant volumes and potentially leading to decreased listing for higher risk recipients.

Review of the discard and/or refusal rate of offered donor hearts to pediatric waitlisted candidates

We aimed to review current literature on the discard rate of donor hearts offered to pediatric recipients and assess geographical differences. Consequences and ways to reduce the discard rate are discussed. A systemic review on published literature on pediatric transplantation published in English since 2010 was undertaken. Additionally, a survey was sent to international OPOs with the goal of incorporating responses from around the world providing a more global picture. Based on the literature review and survey, there is a remarkably wide range of discard and/or refusal for pediatric hearts offered for transplant, ranging between 18% and 57% with great geographic variation. The data suggest that that the overall refusal rate may have decreased over the last decade. Reasons for organ discard were difficult to identify from the available data. Although the refusal rate of pediatric donor hearts seems to be lower compared to that reported in adults, it is still as high as 57% with geographic variation.

ISHLT consensus statement on donor organ acceptability and management in pediatric heart transplantation

The number of potential pediatric heart transplant recipients continues to exceed the number of donors, and consequently the waitlist mortality remains significant. Despite this, around 40% of all donated organs are not used and are discarded. This document (62 authors from 53 institutions in 17 countries) evaluates factors responsible for discarding donor hearts and makes recommendations regarding donor heart acceptance. The aim of this statement is to ensure that no usable donor heart is discarded, waitlist mortality is reduced, and post-transplant survival is not adversely impacted.

Variability in donor selection among pediatric heart transplant providers: Results from an international survey

There is considerable variability in donor acceptance practices among adult heart transplant providers; however, pediatric data are lacking. The aim of this study was to assess donor acceptance practices among pediatric heart transplant professionals. The authors generated a survey to investigate clinicians' donor acceptance practices. This survey was distributed to all members of the ISHLT Pediatric Council in April 2018. A total of 130 providers responded from 17 different countries. There was a wide range of acceptable criteria for potential donors. These included optimal donor-to-recipient weight ratio (lower limit: 50%-150%, upper limit: 120%-350%), maximum donor age (25-75 years), and minimum acceptable left ventricular EF (30%-60%). Non-US centers demonstrated less restrictive donor selection criteria and were willing to accept older donors (50 vs 35 years, P < 0.001), greater size discrepancy (upper limit weight ratio 250% vs 200%, P = 0.009), and donors with a lower EF (45% vs 50%, P < 0.001). Recipient factors were most influential in the decision to accept marginal donors including recipients requiring ECMO support, ventilator support, and highly sensitized patients with a negative XM. However, programmatic factors impacted the decision to decline marginal donors including recent programmatic mortalities and concerns for programmatic restrictions from regulatory bodies. There is significant variation in donor acceptance practices among pediatric heart transplant professionals. Standardization of donor acceptance practices through the development of a consensus statement may help to improve donor utilization and reduce waitlist mortality.

Workshop on the validation and regulatory acceptance of innovative 3R approaches in regulatory toxicology - Evolution versus revolution

At a joint workshop organized by RIVM and BfR, international experts from governmental institutes, regulatory agencies, industry, academia and animal welfare organizations discussed and provided recommendations for the development, validation and implementation of innovative 3R approaches in regulatory toxicology. In particular, an evolutionary improvement of our current approach of test method validation in the context of defined approaches or integrated testing strategies was discussed together with a revolutionary approach based on a comprehensive description of the physiological responses of the human body to chemical exposure and the subsequent definition of relevant and predictive in vitro, in chemico or in silico methods. A more comprehensive evaluation of biological relevance, scientific validity and regulatory purpose of new test methods and assessment strategies together with case studies that provide practical experience with new approaches were discussed as essential steps to build up the necessary confidence to facilitate regulatory acceptance.

Inter-rater and intra-rater reliability and agreement of echocardiographic diagnosis of rheumatic heart disease using the World Heart Federation evidence-based criteria

OBJECTIVE

Different definitions have been used for screening for rheumatic heart disease (RHD). This led to the development of the 2012 evidence-based World Heart Federation (WHF) echocardiographic criteria. The objective of this study is to determine the intra-rater and inter-rater reliability and agreement in differentiating no RHD from mild RHD using the WHF echocardiographic criteria.

METHODS

A standard set of 200 echocardiograms was collated from prior population-based surveys and uploaded for blinded web-based reporting. Fifteen international cardiologists reported on and categorised each echocardiogram as no RHD, borderline or definite RHD. Intra-rater and inter-rater reliability was calculated using Cohen's and Fleiss' free-marginal multirater kappa (κ) statistics, respectively. Agreement assessment was expressed as percentages. Subanalyses assessed reproducibility and agreement parameters in detecting individual components of WHF criteria.

RESULTS

Sample size from a statistical standpoint was 3000, based on repeated reporting of the 200 studies. The inter-rater and intra-rater reliability of diagnosing definite RHD was substantial with a kappa of 0.65 and 0.69, respectively. The diagnosis of pathological mitral and aortic regurgitation was reliable and almost perfect, kappa of 0.79 and 0.86, respectively. Agreement for morphological changes of RHD was variable ranging from 0.54 to 0.93 κ.

CONCLUSIONS

The WHF echocardiographic criteria enable reproducible categorisation of echocardiograms as definite RHD versus no or borderline RHD and hence it would be a suitable tool for screening and monitoring disease progression. The study highlights the strengths and limitations of the WHF echo criteria and provides a platform for future revisions.

Adding Triage Ultrasound to a Breast-Cancer Detection Model in Peru

Background: The rising breast-cancer burden in middle-income countries is straining the capacity of health systems to provide early detection and diagnostic services. To bring these services to women in a northern region of Peru, community education and clinical breast exam (CBE) by midwives was introduced as a method for screening asymptomatic women and evaluating women with symptoms; if positive, women were evaluated further by fine needle aspiration (FNA) by a trained physician at a local hospital. Aim: During the pilot phase, this early detection program resulted in increased demand for cytopathology services, invasive procedures for patients, delays in results, and high rates of benign findings. We added basic triage ultrasound (US), performed and interpreted by general physicians at a local hospital, to further evaluate women with a positive CBE and reduce the number of unnecessary FNAs. We aim to evaluate the changes in the FNA rate. Methods: PATH worked with an expert radiologist to develop a breast-US training program that included: teaching physicians to perform and interpret breast US using a triage algorithm based on the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) and a standardized checklist to document clinical and US findings. The triage algorithm was reviewed and validated by oncologists at Peru's national cancer institute, and later introduced in ten networks in northern Peru. Results: After adding triage ultrasound in 2015, a total of 133 CBE+ women received US at the local hospital; 73 women had a finding on US indicating a need for FNA biopsy, and all received it. Eleven of these women were subsequently diagnosed with breast cancer. Without triage US, all 133 CBE+ women would have received FNA. This represents a 55% decrease (60/133) in FNA biopsies. Conclusion: Triage ultrasound, as part of a resource-adapted model of breast screening, combined with FNA sampling increases the ability of general physicians to manage CBE+ women locally, thereby reducing health system burdens and assuring that patients at highest risk receive timely referrals to a specialized hospital. Triage ultrasound reduces the biopsy rate following a positive CBE. As ultrasound technology becomes more accessible and less expensive, we anticipate there will be an even more significant role for it in early detection models.

Community study to uncover the full spectrum of rheumatic heart disease in Uganda

Objective

Estimates of the prevalence of rheumatic heart disease (RHD) in many endemic countries are limited to samples of children attending schools, which generate an incomplete picture of disease burden in communities. The present study conducted household-based RHD screening in a representative community in Gulu district, Uganda.

Methods

Members of households identified through a two-stage cluster-sampling approach between the ages of 5 years and 50 years were invited to undergo limited cardiac testing with a handheld echocardiogram to assess for the presence of RHD. Suspicious cases underwent confirmatory echocardiogram with a fully functional machine.

Results

Of the 2453 community members screened, 2.45% (95% CI 1.87% to 3.14%) showed echocardiographic evidence of RHD with 1.26% (95% CI 0.860% to 1.79%) having definite RHD. The overall prevalence of RHD among participants <20 years was 2.52% (95% CI 1.78% to 3.45%), with a borderline prevalence of 1.97% (95% CI 1.33% to 2.82%) and a definite prevalence of 0.544% (95% CI 0.235% to 1.07%). Prevalence rates among youth increased with age and peaked in the age group of 16–20 years. The overall adult prevalence (>20 years) of RHD was 2.34% (95% CI 1.49% to 3.49%). The majority of definite cases were mild (81%) and marked by mitral regurgitation and associated morphological valve changes (71%).

Conclusion

Our data reveal a high prevalence of undiagnosed RHD within an endemic community and fill a critical gap in RHD epidemiology in African adults.

Mobile Technology Affinity in Renal Transplant Recipients

BACKGROUND

Medication nonadherence is a common problem in renal transplant recipients (RTRs). Mobile health approaches to improve medication adherence are a current trend, and several medication adherence apps are available. However, it is unknown whether RTRs use these technologies and to what extent. In the present study, the mobile technology affinity of RTRs was analyzed. We hypothesized significant age differences in mobile technology affinity and that mobile technology affinity is associated with better cognitive functioning as well as higher educational level.

METHODS

A total of 109 RTRs (63% male) participated in the cross-sectional study, with an overall mean age of 51.8 ± 14.2 years. The study included the Technology Experience Questionnaire (TEQ) for the assessment of mobile technology affinity, a cognitive test battery, and sociodemographic data.

RESULTS

Overall, 57.4% of the patients used a smartphone or tablet and almost 45% used apps. The TEQ sum score was 20.9 in a possible range from 6 (no affinity to technology) to 30 (very high affinity). Younger patients had significantly higher scores in mobile technology affinity. The only significant gender difference was found in having fun with using electronic devices: Men enjoyed technology more than women did. Mobile technology affinity was positively associated with cognitive functioning and educational level.

CONCLUSIONS

Young adult patients might profit most from mobile health approaches. Furthermore, high educational level and normal cognitive functioning promote mobile technology affinity. This should be kept in mind when designing mobile technology health (mHealth) interventions for RTRs. For beneficial mHealth interventions, further research on potential barriers and desired technologic features is necessary to adapt apps to patients' needs.

Psychometric Properties of the German Version of the Pain Vigilance and Awareness Questionnaire (PVAQ) in Pain-Free Samples and Samples with Acute and Chronic Pain

Purpose

The way individuals attend to pain is known to have a considerable impact on the experience and chronification of pain. One method to assess the habitual “attention to pain” is the Pain Vigilance and Awareness Questionnaire (PVAQ). With the present study, we aimed to test the psychometric properties of the German version of the PVAQ across pain-free samples and across patients with acute and chronic pain.

Method

Two samples of pain-free individuals (student sample (N = 255)/non-student sample (N = 362)) and two clinical pain samples (acute pain patients (N = 105)/chronic pain patients (N = 36)) were included in this cross-sectional evaluation of the German PVAQ. Factor structure was assessed using exploratory and confirmatory factor analyses. Reliability was assessed using internal consistency (Cronbach’s alpha). Construct validity was tested by assessing correlations between PVAQ and theoretically related constructs.

Results

Exploratory factor analysis (non-student sample) and confirmatory factor analysis (student sample, acute pain patient sample) suggested that a two-factor solution best fitted our data (“attention to pain,” “attention to changes in pain”). Internal consistency ranged from acceptable to good in all four samples. As hypothesized, the PVAQ correlated significantly with theoretically related constructs in all four samples, suggesting good construct validity in pain-free individuals and in pain patients.

Conclusion

The German PVAQ shows good psychometric properties across samples of pain-free individuals and patients suffering from pain that are comparable to PVAQ versions of other languages. Thus, the German PVAQ seems to be a measure of pain vigilance equally valid as found in other countries.

Prediction of persistent post-operative pain: Pain-specific psychological variables compared with acute post-operative pain and general psychological variables

BACKGROUND

Psychological variables and acute post-operative pain are of proven relevance for the prediction of persistent post-operative pain. We aimed at investigating whether pain-specific psychological variables like pain catastrophizing add to the predictive power of acute pain and more general psychological variables like depression.

METHODS

In all, 104 young male patients undergoing thoracic surgery for pectus excavatum correction were studied on the pre-operative day (T0) and 1 week (T1) and 3 months (T2) after surgery. They provided self-report ratings (pain-related: Pain Catastrophizing Scale, Pain Anxiety Symptoms Scale = PASS, Pain Vigilance and Awareness Questionnaire = PVAQ; general psychological: Screening for Somatoform Symptoms, State-Anxiety Inventory-X1, Center for Epidemiologic Studies Depression Scale = CES-D). Additional predictors (T1) as well as criterion variables (T2) were pain intensity (Numerical Rating Scale) and pain disability (Pain Disability Index).

RESULTS

Three months after surgery, 25% of the patients still reported clinically relevant pain (pain intensity ≥3) and over 50% still reported pain-related disability. Acute post-operative pain as well as general psychological variables did not allow for a significant prediction of persistent post-operative pain; in contrast, pain-related psychological variables did. The best single predictors were PASS for pain intensity and PVAQ for pain disability.

CONCLUSIONS

Pain-related psychological variables derived from the fear-avoidance model contributed significantly to the prediction of persistent post-operative pain. The best possible compilation of these measures requires further research. More general psychological variables may become relevant predictors later in the medical history.

SIGNIFICANCE

Our results suggest that pain-specific psychological variables such as pain anxiety and pain hypervigilance add significantly to the prediction of persistent post-operative pain and might even outperform established predictors such as acute pain and general psychological variables. Clinicians might benefit from the development of time-economic screening tools based on these variables.

Hybrid Exclusion of HeartMate ІІ Left Ventricular Assist Device After Bridge to Recovery

We present a hybrid technique of left ventricular assist device exclusion after bridge to recovery in a pediatric patient, using percutaneous occlusion of the outflow graft and surgical excision of driveline. This technique has the advantage of avoiding chest reentry and cardiopulmonary bypass.

[Psychological prophylaxis training for coping with postoperative pain. Long-term effects]

INTRODUCTION

The present study was performed to investigate the effect of multidimensional psychological prophylaxis training focusing on coping with cognitive-emotional pain on recovery within the first 12 months after surgery. The training included the following three components: (1) education about pain, analgesia and psychological aspects of coping with pain, (2) training for coping with pain and (3) body-centered relaxation.

MATERIAL AND METHODS

In the study 48 young male patients (surgical correction of a chest malformation) were assessed 1 day before surgery, at discharge and 3, 6 and 12 months postoperatively concerning postoperative pain intensity and pain disability as well as pain anxiety, pain catastrophizing and pain hypervigilance. Additionally, 24 of these patients received training on cognitive-emotional coping with pain 1 day before surgery and 1-3 days after surgery (each session 1 h).

RESULTS

The proportion of patients with clinically relevant improvement was significantly higher in the training group compared to the control group. This was the case for acute pain intensity (approximately 1 week after surgery), pain disability 3 months later and pain anxiety 12 months after surgery.

CONCLUSION

The resurgence of pain anxiety after 12 months could only be found in the control group and could be due to the upcoming surgical removal of the transsternal metal implant. The prophylaxis training can therefore be seen as a protective factor for long-term management of surgery-related consequences and future pain experiences.

Handheld echocardiographic screening for rheumatic heart disease by non-experts

OBJECTIVES

Handheld echocardiography (HAND) has good sensitivity and specificity for rheumatic heart disease (RHD) when performed by cardiologists. However, physician shortages in RHD-endemic areas demand less-skilled users to make RHD screening practical. We examine nurse performance and interpretation of HAND using a simplified approach for RHD screening.

METHODS

Two nurses received training on HAND and a simplified screening approach. Consented students at two schools in Uganda were eligible for participation. A simplified approach (HAND performed and interpreted by a non-expert) was compared with the reference standard (standard portable echocardiography, performed and interpreted by experts according to the 2012 World Heart Federation guidelines). Reasons for false-positive and false-negative HAND studies were identified.

RESULTS

A total of 1002 children were consented, with 956 (11.1 years, 41.8% male) having complete data for review. Diagnoses included: 913 (95.5%) children were classified normal, 32 (3.3%) borderline RHD and 11 (1.2%) definite RHD. The simplified approach had a sensitivity of 74.4% (58.8% to 86.5%) and a specificity of 78.8% (76.0% to 81.4%) for any RHD (borderline and definite). Sensitivity improved to 90.9% (58.7% to 98.5%) for definite RHD. Identification and measurement of erroneous colour jets was the most common reason for false-positive studies (n=164/194), while missed mitral regurgitation and shorter regurgitant jet lengths with HAND were the most common reasons for false-negative studies (n=10/11).

CONCLUSIONS

Non-expert-led HAND screening programmes offer a potential solution to financial and workforce barriers that limit widespread RHD screening. Nurses trained on HAND using a simplified approach had reasonable sensitivity and specificity for RHD screening. Information on reasons for false-negative and false-positive screening studies should be used to inform future training protocols, which could lead to improved screening performance.

The utility of handheld echocardiography for early rheumatic heart disease diagnosis: a field study

AIMS

The World Heart Federation (WHF) guidelines for rheumatic heart disease (RHD) are designed for a standard portable echocardiography (STAND) machine. A recent study in a tertiary care centre demonstrated that they also had good sensitivity and specificity when modified for use with handheld echocardiography (HAND). Our study aimed to evaluate the performance of HAND for early RHD diagnosis in the setting of a large-scale field screening.

METHODS AND RESULTS

STAND was performed in 4773 children in Gulu, Uganda, with 10% randomly assigned to also undergo HAND. Additionally, any child with mitral or aortic regurgitation also underwent HAND. Studies were performed by experienced echocardiographers and blindly reviewed by cardiologists using 2012 WHF criteria, which were modified slightly for HAND--due to the lack of spectral Doppler capability. Paired echocardiograms were performed in 1420 children (mean age 10.8 and 53% female), resulting in 1234 children who were normal, 133 who met criteria for borderline RHD, 47 who met criteria for definite RHD, and 6 who had other diagnoses. HAND had good sensitivity and specificity for RHD detection (78.9 and 87.2%, respectively), but was most sensitive for definite RHD (97.9%). Inter- and intra-reviewer agreement ranged between 66-83 and 71.4-94.1%, respectively.

CONCLUSIONS

HAND has good sensitivity and specificity for diagnosis of early RHD, performing best for definite RHD. Protocols for RHD detection utilizing HAND will need to include confirmation by STAND to avoid over-diagnosis. Strategies that evaluate simplified screening protocols and training of non-physicians hold promise for more wide spread deployment of HAND-based protocols.

Mutations in Alström protein impair terminal differentiation of cardiomyocytes

Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognise homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at two weeks postnatal compared to wild-type littermates. We conclude that deficiency of Alström protein impairs postnatal cardiomyocyte cell cycle arrest.

World Heart Federation criteria for echocardiographic diagnosis of rheumatic heart disease--an evidence-based guideline

Over the past 5 years, the advent of echocardiographic screening for rheumatic heart disease (RHD) has revealed a higher RHD burden than previously thought. In light of this global experience, the development of new international echocardiographic guidelines that address the full spectrum of the rheumatic disease process is opportune. Systematic differences in the reporting of and diagnostic approach to RHD exist, reflecting differences in local experience and disease patterns. The World Heart Federation echocardiographic criteria for RHD have, therefore, been developed and are formulated on the basis of the best available evidence. Three categories are defined on the basis of assessment by 2D, continuous-wave, and color-Doppler echocardiography: 'definite RHD', 'borderline RHD', and 'normal'. Four subcategories of 'definite RHD' and three subcategories of 'borderline RHD' exist, to reflect the various disease patterns. The morphological features of RHD and the criteria for pathological mitral and aortic regurgitation are also defined. The criteria are modified for those aged over 20 years on the basis of the available evidence. The standardized criteria aim to permit rapid and consistent identification of individuals with RHD without a clear history of acute rheumatic fever and hence allow enrollment into secondary prophylaxis programs. However, important unanswered questions remain about the importance of subclinical disease (borderline or definite RHD on echocardiography without a clinical pathological murmur), and about the practicalities of implementing screening programs. These standardized criteria will help enable new studies to be designed to evaluate the role of echocardiographic screening in RHD control.

Onset of Rayleigh-Bénard convection in cylindrical containers

We determined the critical Rayleigh numbers Ra{c} for the onset of convection in cylindrical containers with aspect ratios 1 approximately <Gamma [ triple bond] D/L approximately <9 ( D is the diameter and L the height) and the patterns that form just above Ra{c}, both from experiment and by direct numerical simulation (DNS). Results for Ra{c} agree well with the linear stability analysis by Buell and Catton for containers with finite sidewall conductivity. For Gamma<or=1.58+/-0.10 , we found that the patterns correspond to an azimuthal Fourier mode with mode number m=1 , corresponding to a single convection roll. For 1.58 approximately < Gamma approximately <3.26+/-0.02 , the pattern was a concentric roll, corresponding to m=0 . For 3.26<or=Gamma approximately >4, an m=1 mode was found again, but near Gamma=4 either m=1 or m=2 was observed in different runs. These results are consistent with the marginal stability curves calculated by Buell and Catton in the sense that the mode that is the first as a function of Ra to acquire a positive growth rate is the one that is observed. For Gamma approximately >4, the theoretical marginal curves for the four lowest modes lie very close together. There we found patterns near onset that corresponded to various modes, including m=2 and 4. At relatively large Gamma approximately > 6, we observed parallel straight rolls quite close to onset. Our patterns agree with several DNS investigations by others, but at some Gamma values differ from those observed experimentally by Stork and Müller. Some results for the pattern evolution with increasing Ra are reported as well.

Decline in rejection in the first year after pediatric cardiac transplantation: a multi-institutional study

BACKGROUND

Rejection is a major cause of morbidity and mortality after pediatric heart transplantation (HTx). Survival after pediatric HTx has improved over time, but whether there has been an era-related improvement in the occurrence of allograft rejection is unknown.

METHODS

The Pediatric Heart Transplant Study (PHTS) database was queried for patients who underwent HTx from January 1993 to December 2005 to determine the incidence of rejection and identify factors associated with the first episode of rejection in the first year after HTx.

RESULTS

Data were reviewed in 1,852 patients from 36 centers. The incidence of rejection declined over 13 years at a rate of -2.58 +/- 0.41 (p < 0.001) from approximately 60% to 40% (p < 0.001). The mean number of episodes of rejection also significantly fell at a rate of -0.05 +/- 0.01 per patient/year from 1.19 to 0.66 (p < 0.001). The incidence of rejection with hemodynamic compromise and death from rejection did not change. Multivariate analysis for the risk of a first rejection episode demonstrated decreased risk of rejection with later year of HTx (odds ratio [OR], 0.88; 95% confidence interval [CI], 0.85-0.91; p < 0.001) and use of mechanical support (OR, 0.65; 95% CI, 0.42-0.99; p = 0.046). Increased risk of rejection was associated with positive donor-specific crossmatch (OR, 1.85; 95% CI, 1.18-2.88; p = 0.007) and older recipient age (OR, 1.05; 95% CI, 1.02-1.07; p < 0.001).

CONCLUSIONS

Although the overall incidence and prevalence of rejection has substantially decreased over time in pediatric HTx recipients in the first year after HTx, the rate of rejection with hemodynamic compromise or death from rejection remains unchanged.

Haemophilus influenzae serotype f purulent pericarditis: a cause of death in a child with Down syndrome

Purulent pericarditis is a cardiac emergency that can be difficult to diagnose and can be rapidly fatal. We report the case of a child with Down syndrome and recent atrial and ventricular septal defect repair who died from Haemophilus influenzae serotype f pericarditis.

Prevalence of congenital cardiovascular malformations among relatives of infants with hypoplastic left heart, coarctation of the aorta, and d-transposition of the great arteries

Cardiovascular malformations (CVM) are the most common birth defects and carry significant and lifelong personal and societal costs. Research into genetic and environmental risk factors is therefore critical in identifying clues to causation and prevention. The purpose of this study was to investigate patterns of familial aggregation in CVM, specifically among infants with left-sided obstructive heart defects. We ascertained families of probands with hypoplastic left heart (HLH: N = 38), coarctation of the aorta (CoA: N = 46), and d-transposition of the great arteries (dTGA: N = 22). First degree relatives had clinical examinations and echocardiograms; all other relatives had detailed reviews of medical records. A total of 2,694 relatives were included in the study: 379 1st degree, 986 2nd degree, and 1,329 3rd degree. Mean nuclear family size and sibship size were similar among the groups. CVM were detected more frequently in 1st degree relatives of probands with HLH (19.3%) or CoA (9.4%) than among dTGA families (2.7%). The proportions of affected 2nd degree relatives were similar across groups (</=1%). In 3rd degree relatives, CVM was detected in 1.8% of the HLH families compared to 1.2% in CoA and 0.4% in dTGA families. The predominant types of CVM among relatives of HLH and CoA probands were left-sided obstructive lesions, in 72% (21 of 29) and 67% (25 of 37) of the affected relatives, respectively. Familial aggregation of these types of CVM is therefore confirmed in this study, potentially facilitating the search for specific genetic and other risk factors in recurrent CVM.

Chromosome topology and genome size of selected actinomycetes species

Information about the genome organization of actinomycetes species is restricted to a few genera: Corynebacterium, Mycobacterium, Rhodococcus, Saccharopolyspora and Streptomyces. Streptomyces species and Saccharopolyspora erythraea were shown to contain a single linear 8 Mb chromosome. In contrast, the Corynebacterium, Mycobacterium and Rhodococcus species studied were demonstrated to possess a smaller (3 Mb-6.5 Mb) single circular chromosome. To investigate whether linear chromosome topology and genome sizes above 7 Mb are unique features of Streptomyces and S. erythraea we have started to investigate the chromosome topology, the genome size and the status of accessory elements of additional actinomycetes species: Actinoplanes philippinensis, Amycolatopsis orientalis, Micromonospora chalcea, Nocardia asteroides, Rhodococcus opacus and Streptoverticillium abikoense. Our data which are based on PFGE experiments clearly suggest that large genome sizes and chromosome linearity are seen in mycelium forming actinomycetes genera. In addition we have identified large linear plasmids in Nocardia asteroides, Streptoverticillium abikoense and Rhodococcus opacus.

Genomic structure of the human Ah receptor nuclear translocator gene (hARNT)

The vertebrate basic helix-loop-helix/Per-ARNT-Sim (bHLH/PAS protein) ARNT (aryl hydrocarbon receptor nuclear translocator) plays a crucial role in transcriptional regulation as the common subunit of a number of transcriptionally active complexes. Several studies indicate that ARNT might be involved in the pathogenesis of various genetic diseases. In this study we provide the first report on the genomic structure of the human ARNT gene (hARNT). Human BAC and PAC libraries were screened, and clones positive for ARNT were mapped, subcloned, and sequenced. The gene has an overall size of about 65 kb and consists of 22 exons varying in size from 25 to 214 bp. Splice junctions follow the GT/AG consensus except for intron 11 starting with GC at its 5' end. Knowledge of exon-intron boundaries and intronic sequences neighboring the exons allows the extended search for polymorphisms and variants in human genomic DNA. The exonintron arrangement is highly similar to the murine arnt gene (marnt) except for a slight shift in the last three exons. 5' RACE indicated several transcription start sites, one of them identical with the major transcription start site of marnt.

Conservation and novelty in the evolution of cell adhesion and extracellular matrix genes

New proteins and modules have been invented throughout evolution. Gene "birth dates" in Caenorhabditis elegans range from the origins of cellular life through adaptation to a soil habitat. Possibly half are "metazoan" genes, having arisen sometime between the yeast-metazoan and nematode-chordate separations. These include basement membrane and cell adhesion molecules implicated in tissue organization. By contrast, epithelial surfaces facing the environment have specialized components invented within the nematode lineage. Moreover, interstitial matrices were likely elaborated within the vertebrate lineage. A strategy for concerted evolution of new gene families, as well as conservation of adaptive genes, may underlie the differences between heterochromatin and euchromatin.

Purification and analysis of authentic CLIP-170 and recombinant fragments

We have purified authentic CLIP-170 (cytoplasmic linker protein of 170 kDa) and fragments comprising functional domains of the protein to characterize the structural basis of the function of CLIP-170. Analysis of authentic CLIP-170 and the recombinant fragments by electron microscopy after glycerol spraying/low angle rotary metal shadowing reveals CLIP-170 as a thin, 135-nm-long molecule with two kinks in its central rod domain, which are approximately equally spaced from the two ends of the protein. The central domain consisting of heptad repeats, which is alpha-helical in nature and forms a 2-stranded coiled-coil, mediates dimerization of CLIP-170. The rod domain harbors two kinks, each spaced approximately 37 nm from the corresponding end of the molecule, thus providing mechanical flexibility to the highly elongated molecule. The N-terminal domain of CLIP-170 binds to microtubules in vitro with a stoichiometry of one dimeric head domain per four tubulin heterodimers. Authentic CLIP-170 binds to microtubules with lower stoichiometry, indicating that the rod and tail domains affect microtubule binding of CLIP-170. These results document that CLIP-170 is a highly elongated polar molecule with the microtubule-binding domain and the organelle-interacting domains at opposite ends of the homodimer, thus providing a structural basis for the function of CLIP-170 as a microtubule-organelle linker protein.

Partial kinetoplast-mitochondrial gene organization and expression in the respiratory deficient plant trypanosomatid Phytomonas serpens

In plant-dwelling trypanosomatids from the genus Phytomonas, mitochondrial functions, such as cytochrome mediated respiration, ATP production and Krebs cycle, are missing, and cell energetics is based on the glycolysis. Using Blue Native/Tricine-SDS two-dimensional gel electrophoretic analysis, we observed that mitochondrial respiratory Complexes III (cytochrome bc1) and IV (cytochrome c oxidase) were absent in Phytomonas serpens; however, Complex V (ATPase) was present. A deletion of the genes for cytochrome c oxidase subunit III (COIII) and apocytochrome b (Cyb) was identified within the 6234 bp sequenced region of the 31 kb maxicircle kinetoplast DNA. Genes, found in this region, include 12S and 9S ribosomal RNAs, subunits 7, 8 and 9 of NADH dehydrogenase (ND7, ND8 and ND9) and subunit 6 of ATPase (A6 or MURF4), as well as the genes (MURF1, MURF5 and G3) with unknown function. Most genes are actively transcribed and some mRNAs are edited. Fully edited mRNAs for A6 and G3 were abundant, while edited ND7 transcripts were rare, and only partially edited and pre-edited transcripts for ND8 were detected. The data show that the mitochondrial genome of P. serpens is functional, although its functions may be limited to expressing the ATPase and, possibly, NADH dehydrogenase complexes.

Dissociation of coatomer from membranes is required for brefeldin A-induced transfer of Golgi enzymes to the endoplasmic reticulum

Addition of brefeldin A (BFA) to mammalian cells rapidly results in the removal of coatomer from membranes and subsequent delivery of Golgi enzymes to the endoplasmic reticulum (ER). Microinjected anti-EAGE (intact IgG or Fab-fragments), antibodies against the "EAGE"-peptide of beta-COP, inhibit BFA-induced redistribution of beta-COP in vivo and block transfer of resident proteins of the Golgi complex to the ER; tubulo-vesicular clusters accumulate and Golgi membrane proteins concentrate in cytoplasmic patches containing beta-COP. These patches are devoid of marker proteins of the ER, the intermediate compartment (IC), and do not contain KDEL receptor. Interestingly, relocation of KDEL receptor to the IC, where it colocalizes with ERGIC53 and ts-O45-G, is not inhibited under these conditions. While no stacked Golgi cisternae remain in these injected cells, reassembly of stacks of Golgi cisternae following BFA wash-out is inhibited to only approximately 50%. Mono- or divalent anti-EAGE stabilize binding of coatomer to membranes in vitro, at least as efficiently as GTP(gamma)S. Taken together these results suggest that enhanced binding of coatomer to membranes completely inhibits the BFA-induced retrograde transport of Golgi resident proteins to the ER, probably by inhibiting fusion of Golgi with ER membranes, but does not interfere with the disassembly of the stacked Golgi cisternae and recycling of KDEL receptor to the IC. These results confirm our previous results suggesting that COPI is involved in anterograde membrane transport from the ER/IC to the Golgi complex (Pepperkok et al., 1993), and corroborate that COPI regulates retrograde membrane transport between the Golgi complex and ER in mammalian cells.

Beta-COP is essential for biosynthetic membrane transport from the endoplasmic reticulum to the Golgi complex in vivo

Microinjection of antibodies against a synthetic peptide of a non-clathrin-coated vesicle-associated coat protein, beta-COP, blocks transport of a temperature-sensitive vesicular stomatitis virus glycoprotein (ts-O45-G) to the cell surface. Transport is inhibited upon release of the viral glycoprotein from temperature blocks at 39.5 degrees C (endoplasmic reticulum [ER]) and 15 degrees C (intermediate compartment), but not at 20 degrees C (trans-Golgi network). Ts-O45-G is arrested in tubular membrane structures containing p53 at the interface of the ER and the Golgi stack. This is consistent with inhibition of acquisition of endoglycosidase H resistance of ts-O45-G in injected cells. Secretion of endogenous proteins and maturation of cathepsin D are also inhibited. These data provide in vivo evidence that beta-COP has an important function in biosynthetic membrane traffic in mammalian cells.

CLIP-170 links endocytic vesicles to microtubules

Binding of endocytic carrier vesicles to microtubules depends on the microtubule-binding protein CLIP-170 in vitro. In vivo, CLIP-170 colocalizes with a subset of transferrin receptor-positive endocytic structures and, more extensively, with endosomal tubules induced by brefeldin A. The structure of CLIP-170 has been analyzed by cloning its cDNA. The predicted non-helical C- and N-terminal domains of the homodimeric protein are connected by a long coiled-coil domain. We have identified a novel motif present in a tandem repeat in the N-terminal domain of CLIP-170 that is involved in binding to microtubules. This motif is also found in the Drosophila Glued and yeast BIK1 proteins. These features, together with its very elongated structure, suggest that CLIP-170 belongs to a novel class of proteins, cytoplasmic linker proteins (CLIPs), mediating interactions of organelles with microtubules.

Motor protein independent binding of endocytic carrier vesicles to microtubules in vitro

We have established an in vitro assay to characterize the binding of endocytic carrier vesicles to microtubules. Magnetic beads coated with microtubules were used as an affinity matrix. A fraction from nocodazole-treated cells enriched in endocytic carrier vesicles, labeled with internalized horseradish peroxidase, was used in the binding experiments. Binding of the endocytic carrier vesicles to microtubules in vitro was cytosol-dependent. This activity of cytosolic factors was saturable, heat-sensitive, and insensitive to N-ethyl-maleimide. Binding was sensitive to GTP and ATP. Addition of neuronal microtubule-associated proteins completely abolished binding of the endocytic organelles to microtubules. This binding was independent of the cytosolic microtubule-based motor proteins kinesin and cytoplasmic dynein, since cytosol depleted of these proteins remained fully active. Microtubule-binding proteins from HeLa cells, however, stimulated the interaction of endocytic carrier vesicles with microtubules. Trypsinized vesicles could no longer bind to microtubules in the presence of cytosol. These results suggest that cytosolic microtubule-binding proteins, other than the known microtubule-based motor proteins, as well as membrane proteins are involved in the nucleotide-dependent interaction of endocytic carrier vesicles with microtubules.