Integrating Computational and Biological Hemodynamic Approaches to Improve Modeling of Atherosclerotic Arteries

Atherosclerosis is the primary cause of cardiovascular disease, resulting in mortality, elevated healthcare costs, diminished productivity, and reduced quality of life for individuals and their communities. This is exacerbated by the limited understanding of its underlying causes and limitations in current therapeutic interventions, highlighting the need for sophisticated models of atherosclerosis. This review critically evaluates the computational and biological models of atherosclerosis, focusing on the study of hemodynamics in atherosclerotic coronary arteries. Computational models account for the geometrical complexities and hemodynamics of the blood vessels and stenoses, but they fail to capture the complex biological processes involved in atherosclerosis. Different in vitro and in vivo biological models can capture aspects of the biological complexity of healthy and stenosed vessels, but rarely mimic the human anatomy and physiological hemodynamics, and require significantly more time, cost, and resources. Therefore, emerging strategies are examined that integrate computational and biological models, and the potential of advances in imaging, biofabrication, and machine learning is explored in developing more effective models of atherosclerosis.

Be still, my beating heart: reading pulselessness from Shakespeare to the artificial heart

Today, patients with heart failure can be kept alive by an artificial heart while they await a heart transplant. These modern artificial hearts, or left ventricular assist devices (LVADs), remove the patient's discernible pulse while still maintaining life. This technology contradicts physiological, historical and sociocultural understandings of the pulse as central to human life. In this essay, we consider the ramifications of this contrast between the historical and cultural importance placed on the pulse (especially in relation to our sense of self) and living with a pulseless LVAD. We argue that the pulse's relationship to individual identity can be rescripted by examining its representation in formative cultural texts like the works of William Shakespeare. Through an integration of historical, literary and biomedical engineering perspectives on the pulse, this paper expands interpretations of pulselessness and advocates for the importance of cultural-as well as biomedical-knowledge to support patients with LVADs and those around them. In reconsidering figurative and literal representations of the heartbeat in the context of technology which removes the need for a pulse, this essay argues that narrative and metaphor can be used to reconceptualise the relationship between the heartbeat and identity.

A computational framework for adjusting flow during peripheral extracorporeal membrane oxygenation to reduce differential hypoxia

Peripheral veno-arterial extra corporeal membrane oxygenation (VA-ECMO) is an established technique for short-to-medium support of patients with severe cardiac failure. However, in patients with concomitant respiratory failure, the residual native circulation will provide deoxygenated blood to the upper body, and may cause differential hypoxemia of the heart and brain. In this paper, we present a general computational framework for the identification of differential hypoxemia risk in VA-ECMO patients. A range of different VA-ECMO patient scenarios for a patient-specific geometry and vascular resistance were simulated using transient computational fluid dynamics simulations, representing a clinically relevant range of values of stroke volume and ECMO flow. For this patient, regardless of ECMO flow rate, left ventricular stroke volumes greater than 28 mL resulted in all aortic arch branch vessels being perfused by poorly-oxygenated systemic blood sourced from the lungs. The brachiocephalic artery perfusion was almost entirely derived from blood from the left ventricle in all scenarios except for those with stroke volumes less than 5 mL. Our model therefore predicted a strong risk of differential hypoxemia in nearly all situations with some residual cardiac function for this combination of patient geometry and vascular resistance. This simulation highlights the potential value of modelling for optimising ECMO design and procedures, and for the practical utility for personalised approaches in the clinical use of ECMO.

Flow mixing during peripheral veno-arterial extra corporeal membrane oxygenation - A simulation study

Peripheral veno-arterial extra-corporeal membrane oxygenation (ECMO) is an artificial circulation that supports patients with severe cardiac and respiratory failure. Differential hypoxia during ECMO support has been reported, and it has been suggested that it is due to the mixing of well-perfused retrograde ECMO flow and poorly-perfused antegrade left ventricle (LV) flow in the aorta. This study aims to quantify the relationship between ECMO support level and location of the mixing zone (MZ) of the ECMO and LV flows. Steady-state and transient computational fluid dynamics (CFD) simulations were performed using a patient-specific geometrical model of the aorta. A range of ECMO support levels (from 5% to 95% of total cardiac output) were evaluated. For ECMO support levels above 70%, the MZ was located in the aortic arch, resulting in perfusion of the arch branches with poorly perfused LV flow. The MZ location was stable over the cardiac cycle for high ECMO flows (>70%), but moved 5cm between systole and diastole for ECMO support level of 60%. This CFD approach has potential to improve individual patient care and ECMO design.

Amplitude variability over trials in hemodynamic responses in adolescents with ADHD: The role of the anterior default mode network and the non-specific role of the striatum

It has been suggested that intra-individual variability (IIV) in performance on attention and other cognitive tasks might be a cognitive endophenotype in individuals with ADHD. Despite robust IIV findings in behavioral data, only sparse data exist on how what type of brain dysfunction underlies variable response times. In this study, we asked whether ADHD IIV in reaction time on a commonly-used test of attention might be related to variation in hemodynamic responses (HRs) observed trial-to-trial. Based on previous studies linking IIV to regions within the “default mode” network (DMN), we predicted that adolescents with ADHD would have higher HR variability in the DMN compared with controls, and this in turn would be related to behavioral IIV. We also explored the influence of social anxiety on HR variability in ADHD as means to test whether higher arousal associated with high trait anxiety would affect the neural abnormalities. We assessed single-trial variability of HRs, estimated from fMRI event-related responses elicited during an auditory oddball paradigm in adolescents with ADHD and healthy controls (11–18 years old; N = 46). Adolescents with ADHD had higher HR variability compared with controls in anterior regions of the DMN. This effect was specific to ADHD and not associated with traits of age, IQ and anxiety. However, an ADHD effect of higher HR variability also appeared in a basal ganglia network, but for these brain regions the relationships of HR variability and social anxiety levels were more complex. Performance IIV correlated significantly with variability of HRs in both networks. These results suggest that assessment of trial-to-trial HR variability in ADHD provides information beyond that detectable through analysis of behavioral data and average brain activation levels, revealing specific neural correlates of a possible ADHD IIV endophenotype.

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We studied if the behavioral variability in ADHD is also found on a neuronal level.

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Independent component analysis was combined with BOLD amplitude variability.

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Adolescents with ADHD had higher amplitude variability than healthy controls.

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Higher amplitude variability was shown in an anterior default mode network.

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Social anxiety in ADHD associated with high amplitude variability in the striatum

Synovial sarcoma in children and adolescents: the European Pediatric Soft Tissue Sarcoma Study Group prospective trial (EpSSG NRSTS 2005)

BACKGROUND

To report the results of the first European prospective nonrandomized trial dedicated to pediatric synovial sarcoma.

PATIENTS AND METHODS

From August 2005 to August 2012, 138 patients <21 years old with nonmetastatic synovial sarcoma were registered in 9 different countries (and 60 centers). Patients were treated with a multimodal therapy including ifosfamide-doxorubicin chemotherapy and radiotherapy, according to a risk stratification based on surgical stage, tumor size and site, and nodal involvement.

RESULTS

With a median follow-up of 52.1 months (range 13.8-104.4 months), event-free survival (EFS) was 81.9% and 80.7%, and overall survival (OS) was 97.2% and 90.7%, at 3 and 5 years, respectively. The only significant prognostic variable at univariate analysis was the risk group: 3-year EFS was 91.7% for low-risk, 91.2% for intermediate-risk, and 74.4% for high-risk cases. In 24 low-risk patients (completely resected tumor ≤5 cm in size) treated with surgery alone, there were two local relapses and no metastatic recurrences. Among 67 high-risk patients (unresected, or axial tumor or nodal involvement), 66 underwent surgery after neoadjuvant chemotherapy. Response to chemotherapy was 55.2%, including 22.4% cases with complete or major partial remissions, and 32.8% with minor partial remissions.

CONCLUSION

This study demonstrates that collaborative prospective studies on rare pediatric sarcomas are feasible even on a European scale, with excellent treatment compliance. The overall results of treatment were satisfactory, with higher survival rates than those previously published by pediatric groups. Nonetheless, larger, international projects are needed, based on a cooperative effort of pediatric and adult oncologists.

CLINICAL TRIALS NUMBER

European Union Drug Regulating Authorities Clinical Trials No. 2005-001139-31.

Frank-starling control of a left ventricular assist device

A physiological control system was developed for a rotary left ventricular assist device (LVAD) in which the target pump flow rate (LVADQ) was set as a function of left atrial pressure (LAP), mimicking the Frank-Starling mechanism. The control strategy was implemented using linear PID control and was evaluated in a pulsatile mock circulation loop using a prototyped centrifugal pump by varying pulmonary vascular resistance to alter venous return. The control strategy automatically varied pump speed (2460 to 1740 to 2700 RPM) in response to a decrease and subsequent increase in venous return. In contrast, a fixed-speed pump caused a simulated ventricular suction event during low venous return and higher ventricular volumes during high venous return. The preload sensitivity was increased from 0.011 L/min/mmHg in fixed speed mode to 0.47L/min/mmHg, a value similar to that of the native healthy heart. The sensitivity varied automatically to maintain the LAP and LVADQ within a predefined zone. This control strategy requires the implantation of a pressure sensor in the left atrium and a flow sensor around the outflow cannula of the LVAD. However, appropriate pressure sensor technology is not yet commercially available and so an alternative measure of preload such as pulsatility of pump signals should be investigated.

Semi-blind ICA of fMRI: A method for utilizing hypothesis-derived time courses in a spatial ICA analysis

Independent component analysis (ICA) is a data-driven approach utilizing high-order statistical moments to find maximally independent sources that has found fruitful application in functional magnetic resonance imaging (fMRI). Being a blind source separation technique, ICA does not require any explicit constraints upon the fMRI time courses. However, for some fMRI data analysis applications, such as for the analysis of an event-related paradigm, it would be useful to flexibly incorporate paradigm information into the ICA analysis. In this paper, we present an approach for constrained or semi-blind ICA (sbICA) analysis of event-related fMRI data by imposing regularization on certain estimated time courses using the paradigm information. We demonstrate the performance of our approach using both simulations and fMRI data from a three-stimulus auditory oddball paradigm. Simulation results suggest that (1) a regression approach slightly outperforms ICA when prior information is accurate and ICA outperforms the general linear model (GLM)-based approach when prior information is not completely accurate, (2) prior information improves the robustness of ICA in the presence of noise, and (3) ICA analysis using prior information with temporal constraints can outperform a regression approach when the prior information is not completely accurate. Using fMRI data, we compare a regression-based conjunction analysis of target and novel stimuli, both of which elicit an orienting response, to an sbICA approach utilizing both the target and novel stimuli to constrain the ICA time courses. Results show similar positive associations for both GLM and sbICA, but sbICA detects additional negative associates consistent with regions implicated in a default mode of brain activity. This suggests that task-related default mode decreases have a more "complex" signal that benefits from a flexible modeling approach. Compared with a traditional GLM approach, the sbICA approach provides a flexible way to analyze fMRI data that reduces the assumptions placed upon the hemodynamic response of the brain. The advantages and limitations of our technique are discussed in detail in the manuscript to provide guidelines to the reader for developing useful applications. The use of prior time course information in a spatial ICA analysis, which combines elements of both a regression approach and a blind ICA approach, may prove to be a useful tool for fMRI analysis.

fMRI analysis with the general linear model: removal of latency-induced amplitude bias by incorporation of hemodynamic derivative terms

Functional magnetic resonance imaging (fMRI) data are often analyzed using the general linear model employing a hypothesized neural model convolved with a hemodynamic response function. Mismatches between this hemodynamic model and the data can be induced by spatially varying delays or slice-timing differences. It is common practice to desensitize the analysis to such delays by incorporation of the hemodynamic model plus its temporal derivative. The rationale often used is that additional variance will be captured and regressed out from the data. Though this is true, it ignores the potential for amplitude bias induced by small model mismatches due to, for example, variable hemodynamic delays and is not helpful for "random effects" analyses which typically do not account for the first level variance at all. Amplitude bias is due to the use of only the nonderivative portion of the model in the final test for significant amplitudes. We propose instead testing an amplitude value that is a function of both the nonderivative and the derivative terms of the model. Using simulations, we show that the proposed amplitude test does not suffer from delay-induced bias and that a model incorporating temporal derivatives is a more natural test for amplitude differences. The proposed test is applied in a random-effects analysis of 100 subjects. It reveals increased amplitudes in areas consistent with the task, with the largest increases in regions with greater hemodynamic delays.

Relationship of cognitive ability to the developmental course of antisocial behavior in substance-dependent patients

1. The present study examined cognitive differences among three groups of abstinent substance-dependent patients and a control group of non-drug users. The patient groups were defined according to their DSM III-R substance dependence diagnosis(es): heroin, cocaine, or dual alcohol and cocaine dependence. 2. In the initial analysis, which compared the four subject groups on scores from the Shipley Institute of Living Scale, no significant differences were found. However, the groups did vary on the number of Antisocial Personality Disorder (ASPD) behaviors. 3. Another set of analyses was conducted to examine the relationship between ASPD and SILS scores. Analyses of the effects of ASPD (+/-) across all of the patients revealed lower SILS scores in the ASPD-positive group. Additional analyses examined the developmental course of the ASPD effect by contrasting 1) patient groups characterized by childhood Conduct Disorder (CD) combined with adult ASPD vs. 2) childhood CD which did not continue into adulthood as ASPD vs. 3) adults who did not report childhood CD but who met other ASPD behavioral criteria as adults, vs. 4) subjects who had neither childhood CD nor adult ASPD. 4. In this analysis, it was found that patients who met diagnostic criteria for childhood Conduct Disorder, but whose antisocial behaviors resolved after age 15, had equivalent SILS scores to those patients with no childhood CD or adult ASPD. A decrement in SILS scores was only found in those patients whose antisocial behaviors persisted into adulthood. 5. ASPD adults who did not report childhood CD behaviors had normal SILS scores compared to Controls.

Survival of children with soft-tissue sarcoma in Europe since 1978: results from the EUROCARE study

Soft-tissue sarcomas account for 5--8% of all childhood cancers in European countries. In the EUROCARE childhood cancer study, there were 2163 registrations from 17 countries for soft-tissue sarcomas in patients aged 0--14 years during 1978--1989. Of this total, three-quarters were contributed by childhood cancer registries in Germany and the UK. Age-standardised 5-year survival rates of children diagnosed during 1985--1989 were 65% (95% confidence interval (CI) 56--72) for rhabdomyosarcoma, 68% (95% CI 58--77) for fibrosarcoma, 78% (95% CI: 64--87) for other specified soft-tissue sarcomas except Kaposi's and 51% (95% CI 37--65) for 'unspecified' soft-tissue sarcomas. Survival rates increased steadily throughout the 12-year study period for all soft-tissue sarcomas combined, but the increase took place predominantly in the early 1980s for rhabdomyosarcoma. Improvements in survival which had previously been reported from individual countries and in clinical series are confirmed as having taken place throughout much of Europe on a population basis. In a supplementary analysis, there was little indication of a further improvement during 1990--1992.

Connecticut Pictorial Learning Test: a pictorial version of the California Verbal Learning Test

This paper describes the development of a pictorial version of the California Verbal Learning Test. The new instrument, named the Connecticut Pictorial Learning Test (COPLT), was tested in two experiments. The first experiment involved selection and testing of new verbal stimuli to be adapted for pictorial use. Results suggest that these new items are approximately equivalent in difficulty to the original CVLT stimuli. These stimuli can serve as CVLT alternate Form III for use in clinical verbal memory research. Recall means and standard deviations are provided for the new stimulus set with a young adult sample. The second experiment explores the psychometric properties of the new COPLT after stimuli were translated into pictorial form. The psychometric evidence suggests that the pictorial test has good internal consistency and concurrent validity with widely-used clinical memory tests. Furthermore, verbally-mediated information processing serves successful pictorial learning and subsequent recall performance in normal healthy control subjects when verbally-encodable pictorial stimuli are used. The use of semantic organization appears to be even more important for optimal performance using pictorial stimuli than with verbal stimuli. Scoring rules for the COPLT are included in the Appendix.

Treatment of orbital rhabdomyosarcoma: survival and late effects of treatment--results of an international workshop

PURPOSE

Orbital rhabdomyosarcoma (RMS) historically has been associated with an excellent survival rate. The majority of patients are cured with the use of both chemotherapy and radiation therapy, but a significant number experience important late sequelae of treatment. In an attempt to determine optimal therapy in relation both to cure and to sequelae, the experience of the four international collaborative groups (Intergroup Rhabdomyosarcoma Study Group [IRSG], International Society of Paediatric Oncology [SIOP] Sarcoma Committee, German Collaborative Soft Tissue Sarcoma Group [CWS], and Italian Cooperative Soft Tissue Sarcoma Group [ICG] studies) was shared at an international workshop.

PATIENTS AND METHODS

A total of 306 eligible patients were identified from group records (186 from IRS, 43 from SIOP MMT, 40 from CWS, and 37 from ICG). Median age was 6.8 years, and median follow-up was 6.5 years. Eighty percent of patients received radiation therapy (RT) as part of primary therapy, but there were significant differences in the use of RT between the individual groups (93% in IRSG, 76% in ICG, and 70% in CWS, but only 37% in the SIOP MMT group).

RESULTS

At 10 years, event-free and overall survival for the whole cohort were 77% (range, 71% to 81%) and 87% (range, 82% to 92%), respectively. There was no difference in overall survival between the collaborative groups regardless of differences in the use of initial RT. In total, 34 (12%) of 273 survivors had not received RT, although this varied between the different groups (41% in the SIOP MMT group, 20% in CWS, 7% in ICG, and 6% in IRSG). There was no difference in overall survival for the whole cohort regardless of whether radiotherapy was used as part of initial therapy (86% at 10 years for both).

CONCLUSION

These data suggest that a subset of patients with orbital RMS can be cured without systematic local therapy, although the total burden of treatment (primary therapy and treatment for relapse) must be taken into account when assessing the implications for late sequelae.

Season of birth effects in autism

This study examined a sample of preschool-age children with autism in an attempt to identify patterns of birth dates that deviated from expected frequencies by month or season. Birth dates of children with autism and those of a non-autistic sibling control group were compared to the number of total live births gathered from U.S. Census data. Analyses included two types of chi-square analyses and a seasonal harmonic trend analysis. Previously unmentioned in the literature is a seasonal effect finding for females within the entire sample, and both a seasonal and monthly effect for children classified as socially Passive by the Wing system. A significant elevation was also found in March within the Boston sub-sample (n = 37). This sample largely comprised low-functioning boys with autism, a finding consistent with previous findings in the literature. Peri-natal complications and early life development of the subjects from the Boston site are detailed.

Risk factors for nephrotoxicity after ifosfamide treatment in children: a UKCCSG Late Effects Group study. United Kingdom Children's Cancer Study Group

The aim of this multicentre study was to document the nephrotoxicity associated with ifosfamide and evaluate risk factors in 148 children and young people with sarcomas who underwent investigation of renal function on one occasion each, at a median of 6 (range 1-47) months after completion of ifosfamide (median dose 62.0 (range 6.1-165.0) g/m2). Investigations included glomerular filtration rate (GFR), serum bicarbonate (HCO3) and phosphate (PO4), and renal tubular threshold for phosphate (Tmp/GFR). A clinically relevant nephrotoxicity score' was derived. GFR was < 90 ml/min/1.73 m2 in 61 of 123 evaluable patients, Tmp/GFR < 0.9-1.1 mmol/l (age-dependent) in 45/103, serum PO4 < 0.9-1.mmol/l (age-dependent) in 28/135, and serum HCO3 < 20 (< 18 in infants) mmol/l in 22/95. Of 76 fully evaluable patients: 50% had mild, 20% moderate and 8% severe nephrotoxicity. Higher total ifosfamide dose correlated significantly with greater glomerular and tubular toxicity (P < 0.01); other risk factors, including age at treatment, demonstrated no consistent significant independent effect. Chronic ifosfamide-related glomerular and proximal tubular toxicity were common in this large comprehensive study. Restriction of total ifosfamide dose to < 84 g/m2 will reduce the frequency of, but not abolish, clinically significant nephrotoxicity, whilst doses > 119 g/m2 are associated with a very high risk of severe toxicity.

Subgroups of children with autism by cluster analysis: a longitudinal examination

OBJECTIVES

A hierarchical cluster analysis was conducted using a sample of 138 school-age children with autism. The objective was to examine (1) the characteristics of resulting subgroups, (2) the relationship of these subgroups to subgroups of the same children determined at preschool age, and (3) preschool variables that best predicted school-age functioning.

METHOD

Ninety-five cases were analyzed.

RESULTS

Findings support the presence of 2 subgroups marked by different levels of social, language, and nonverbal ability, with the higher group showing essentially normal cognitive and behavioral scores. The relationship of high- and low-functioning subgroup membership to levels of functioning at preschool age was highly significant.

CONCLUSIONS

School-age functioning was strongly predicted by preschool cognitive functioning but was not strongly predicted by preschool social abnormality or severity of autistic symptoms. The differential outcome of the 2 groups shows that high IQ is necessary but not sufficient for optimal outcome in the presence of severe language impairment.

The acridonecarboxamide GF120918 potently reverses P-glycoprotein-mediated resistance in human sarcoma MES-Dx5 cells

The doxorubicin-selected, P-glycoprotein (P-gp)-expressing human sarcoma cell line MES-Dx5 showed the following levels of resistance relative to the non-P-gp-expressing parental MES-SA cells in a 72 h exposure to cytotoxic drugs: etoposide twofold, doxorubicin ninefold, vinblastine tenfold, taxotere 19-fold and taxol 94-fold. GF120918 potently reversed resistance completely for all drugs. The EC50s of GF120918 to reverse resistance of MES-Dx5 cells were: etoposide 7+/-2 nM, vinblastine 19+/-3 nM, doxorubicin 21+/-6 nM, taxotere 57+/-14 nM and taxol 91+/-23 nM. MES-Dx5 cells exhibited an accumulation deficit relative to the parental MES-SA cells of 35% for [3H]-vinblastine, 20% for [3H]-taxol and [14C]-doxorubicin. The EC50 of GF120918, to reverse the accumulation deficit in MES-Dx5 cells, ranged from 37 to 64 nM for all three radiolabelled cytotoxics. [3H]-vinblastine bound saturably to membranes from MES-Dx5 cells with a KD of 7.8+/-1.4 nM and a Bmax of 5.2+/-1.6 pmol mg(-1) protein. Binding of [3H]-vinblastine to P-gp in MES-Dx5 membranes was inhibited by GF120918 (K = 5+/-1 nM), verapamil (Ki = 660+/-350 nM) and doxorubicin (Ki = 6940+/-2100 nM). Taxol, an allosteric inhibitor of [3H]-vinblastine binding to P-gp, could only displace 40% of [3H]-vinblastine (Ki = 400+/-140 nM). The novel acridonecarboxamide derivative GF120918 potently overcomes P-gp-mediated multidrug resistance in the human sarcoma cell line MES-Dx5. Detailed analysis revealed that five times higher GF120918 concentrations were needed to reverse drug resistance to taxol in the cytotoxicity assay compared to doxorubicin, vinblastine and etoposide. An explanation for this phenomenon had not been found.

Conservative treatment for girls with nonmetastatic rhabdomyosarcoma of the genital tract: A report from the Study Committee of the International Society of Pediatric Oncology

PURPOSE

To report the results of a conservative multimodal approach in girls with nonmetastatic rhabdomyosarcoma (RMS) of the genital tract, treated in International Society of Pediatric Oncology (SIOP) Malignant Mesenchymal Tumors 84 and 89 protocols.

PATIENTS AND METHODS

From 1984 to 1994, 38 girls with RMS of the genital tract (vulva, vagina, uterus) were treated in SIOP protocols. With the exception of patients with rare small tumors, which were resected at the start of the studies, all patients received initial chemotherapy (CHT) (ifosfamide, vincristine, and actinomycin D). Local treatment including surgery, brachytherapy (BT), and external-beam radiotherapy (ERT) was given only to girls who did not achieve complete remission (CR) with CHT or who subsequently relapsed.

RESULTS

The primary tumor originated in the vulva or vagina in 27 girls and in the uterus in 11. The overall survival rate (+/- SE) was 91% +/- 6% at 5 years, and the event-free survival rate was 78% +/- 7%. At a median follow-up of 5 years, 30 girls were alive and in first CR and five were alive and in second CR. Four patients treated with complete resection of the tumor at diagnosis received less CHT. Thirteen patients were treated with CHT alone. In 17 patients, local treatment was necessary to achieve complete local control, for a residual mass after initial CHT (10 patients), for viable tumor on biopsy (three patients), or for local relapse (four patients). The local treatment used was radiotherapy (RT) (ERT in three patients, BT in seven), radical surgery with uterine ablation (three patients), RT and radical surgery (three patients), and conservative surgery with RT (one patient).

CONCLUSION

Girls with nonmetastatic RMS of the genital tract have an excellent prognosis. We found no difference in outcome between uterine and vulvovaginal RMS. Local treatment does not seem necessary in patients who have a complete response to CHT. When a local treatment is needed, BT may be an alternative to radical surgery or ERT.

Pediatric oncology and hematology in Birmingham, England

The hematology and oncology service at Birmingham Children's Hospital was established in the late 1960s and now is one of the largest in the United Kingdom. It provides comprehensive care for the entire range of childhood malignancies, coagulation disorders, and hemoglobinopathies and other hematological disorders, and undertakes bone marrow transplant and megatherapy/peripheral blood stem cell procedures. Research includes clinical trials of treatments of childhood cancers; molecular biology studies on leukemia, Hodgkin's disease, neuroblastoma, and sarconas; childhood cancer epidemiology, and geographical and racial incidence; and treatment of hemophilia and molecular investigation of coagulation disorders. These activities involve collaboration with local, national, and international research groups.

Binomial cokriging for estimating and mapping the risk of childhood cancer

The incidences of human diseases vary from place to place, and this is also likely to be so for the risk of people developing many of them. We have analysed the spatial distribution of childhood cancer in the West Midland Health Authority Region of England from 1980 to 1984. This is a rare disease which is considered to be noncontagious. The observed frequencies of the disease in the electoral wards have been converted to proportions that estimate the risk of a child's developing it. The spatial autocorrelation of the risk, expressed in the variogram, was determined in a novel way from the proportions within electoral wards by treating them as binomial variables dependent on the risk and the numbers of children in the wards. The observed variogram was modelled by Whittle's elementary two-dimensional correlation. Covariances of the proportion and cross covariances between the proportion and the risk were derived, and from the latter and the proportions the risk was estimated in two ways by a form of cokriging: ordinary and conditional unbiased cokriging. The variogram of the risk shows strong autocorrelation, and the kriged estimates, when mapped, have a distribution that is far from even. There are patches where the estimated risk is large, especially in the rural south west and the suburban north east; and there are other patches, notably the more densely populated areas, where it is small.

Phase I study of temozolomide in paediatric patients with advanced cancer. United Kingdom Children's Cancer Study Group

A phase I study of temozolomide administered orally once a day, on 5 consecutive days, between 500 and 1200 mg m(-2) per 28-day cycle was performed. Children were stratified according to prior craniospinal irradiation or nitrosourea therapy. Sixteen of 20 patients who had not received prior craniospinal irradiation or nitrosourea therapy were evaluable. Myelosuppression was dose limiting, with Common Toxicity Criteria (CTC) grade 4 thrombocytopenia occurring in one of six patients receiving 1000 mg m(-2) per cycle, and two of four patients treated at 1200 mg m(-2) per cycle. Therefore, the maximum-tolerated dose (MTD) was 1000 mg m(-2) per cycle. The MTD was not defined for children with prior craniospinal irradiation because of poor recruitment. Plasma pharmacokinetic analyses showed temozolomide to be rapidly absorbed and eliminated, with linear increases in peak plasma concentrations and systemic exposure with increasing dose. Responses (CR and PR) were seen in two out of five patients with high-grade astrocytomas, and one patient had stable disease. One of ten patients with diffuse intrinsic brain stem glioma achieved a long-term partial response, and a further two patients had stable disease. Therefore, the dose recommended for phase II studies in patients who have not received prior craniospinal irradiation or nitrosoureas is 1000 mg m(-2) per cycle. Further evaluation in diffuse intrinsic brain stem gliomas and other high-grade astrocytomas is warranted.

The health status of adult survivors of cancer in childhood

The success of treatment for children with cancer has resulted in a growing population of adult survivors, yet these individuals may be at risk of serious long-term health problems as a result of the treatment they have received. This study explores the pattern of morbidity within a population of 290 adult survivors of cancer in childhood assessed at a median of over 15 years from diagnosis. Acute lymphoblastic leukaemia (33%) and Hodgkin's disease (15%) were the most common primary diagnoses represented. 85% of the whole group had received treatment with chemotherapy, 81% with radiotherapy, 48% with significant surgery and 28% with all three modalities. Overall, 58% of the survivors had at least one 'chronic medical problem' and 32%, two or more. Infertility (14%), nephrectomy (11%), thyroid hormone deficiency (9%), visual handicap (9%), sex hormone (7%) and growth hormone (7%) replacement therapy were the most common problems. Compliance with long term follow-up was good and an audit of an unselected sub group of all the survivors in the study showed that 84% had attended for surveillance over a period of 1 year, accounting for 222 visits of follow up clinics: 15% were also attending other specialist follow-up including psychiatry, orthopaedic, endocrine, dental and cardiac clinics. In conclusion, survivors of cancer in childhood experience actual or potential threats to future health. More than half have at least one chronic medical problem and demonstrate a significant use of medical resources. These data support the need for the continuing follow-up of survivors of cancer in childhood into adult life and the provision of the resources to do so. Optimal patterns of care and future approaches to the reduction of sequelae in future generations of survivors are discussed.

Acute and chronic increases in excitability in rat hippocampal slices after perinatal hypoxia In vivo

We have previously shown that hypoxia induces both acute and chronic epileptogenic effects that are age dependent. Global hypoxia (3-4% O2) induces seizure activity in the developing brain [postnatal day (P)10-12] but not at younger or older ages. Adult rats with prior seizures induced by hypoxia at P10 show increased seizure susceptibility to chemical convulsants compared with controls. In the present study, we tested the hypothesis that acute and chronic epileptogenic effects of hypoxia are demonstrable in hippocampus both in vivo and in vitro. Depth electrode recordings confirmed the presence of ictal activity within hippocampus in P10 rats during global hypoxia. Hippocampal slices prepared from P10 pups killed at 10 min after recovery from hypoxia showed evidence of increased excitability. Extracellular field recordings revealed that the amplitude and duration of long-term potentiation (LTP) was increased significantly in area CA1 of hippocampal slices removed from hypoxic pups. In addition, extracellular recordings within areas CA1 and CA3 showed significantly longer afterdischarge durations in response to kindling stimuli in slices from hypoxic pups compared with controls. To evaluate whether there were also long-term changes in hippocampal excitability, hippocampal slices were prepared from adult rats that had underwent hypoxia at P10 and compared with slices from adult litter-mate controls. A Mg2+-free medium was superfused to induce epileptiform activity within the slices. Extracellular recordings from stratum pyramidale of area CA1 showed that Mg2+-free media induced significantly more frequent ictal discharges in slices from previously hypoxic rats compared with controls. These results provide evidence that the naturally occurring stimulus of hypoxia can result in both acute and chronic changes in the excitability of the CA1 neuronal network. These results parallel our previous in vivo studies demonstrating that global hypoxia acutely increases excitability in the immature brain and that hypoxia during the age window approximately P10 results in long-lasting increases in seizure susceptibility within hippocampus. Our results suggest that the age-dependent epileptogenic effects of hypoxia are in part mediated by a direct and permanent effect on neuronal excitability within hippocampal neuronal networks.

Granulocyte colony-stimulating factor in established febrile neutropenia: a randomized study of pediatric patients

PURPOSE

Infection in neutropenic patients is potentially life-threatening and carries important implications for hospital resource use. Prophylactic administration of cytokines may reduce the severity of neutropenia, but involves the treatment of all patients for the possible benefit of a minority. This study evaluates whether treatment with cytokines in the setting of established febrile neutropenia will influence outcome and be potentially more cost-effective.

PATIENTS AND METHODS

In a double-blind study, pediatric patients with fever and severe neutropenia were randomized to receive granulocyte colony-stimulating factor ([G-CSF] filgrastim; 5 microg/kg/d) or placebo, in addition to antibiotics. The study protocol required a resolution of fever and a neutrophil count > or = 0.2 x 10(9)/L for hospital discharge. Patients could be randomized for up to four independent febrile episodes. A total of 186 episodes of febrile neutropenia were investigated.

RESULTS

Patients randomized to G-CSF had a shorter hospital stay (median, 5 v 7 days; P = .04) and fewer days of antibiotic use (median, 5 v 6 days; P = .02). G-CSF-treated patients also had more rapid neutrophil recovery and higher neutrophil levels at discharge. The 2-day reduction in hospital stay reduced the median bed cost by 29% per patient admission (P = .04).

CONCLUSION

Under the clinical guidelines of our institution, the use of G-CSF in the treatment of established febrile neutropenia produced a small but significant reduction in the time that children required antibiotics and hospital admission, with possible cost savings.

Desmoplastic small round cell tumour of childhood: a report of four cases demonstrating wider clinical features and variable outcome

Purpose. Four further cases of desmoplastic small round cell tumour with multi phenotypic differentiation are described.Subjects. Two patients were typical (male, adolescent with peritoneal tumour and, in one case, liver metastases) and did not respond well to treatment. Two other patients showed less usual features (young, female with retroperitoneal disease, both with intraspinal extension and renal tract obstruction). Both responded favourably to multi-modal treatment regimens including extensive and invasive supportive care.Results. Histologically, all tumours showed clear features of this diagnosis, namely angulated nests of small cells in a background of fibrovascular stroma. Immunohistochemistry typically showed divergent differentiation with neural, muscle and epithelial marker positivity. All four tumours stained positive for the Wilms' tumour 1 suppressor gene product. Electron microscopy showed intercellular tight junctions, cytoplasmatic intermediate filaments and absence of microvilli. Rare neurosecretory-type granules were observed.Discussion. These cases illustrate a broader spectrum of clinical presentation than previously associated with this diagnosis.

The need for specialist review of pathology in paediatric cancer

A retrospective histopathological review of 2104 cases of solid tumour was carried out to assess the variability in diagnosis of childhood cancer. Cases were subject to three independent, concurrent opinions from a national panel of specialist pathologists. The conformity between them was analysed using the percentage of agreement and the kappa statistic (kappa), a measure of the level of agreement beyond that which could occur by chance alone, and weighted kappa (w kappa), which demonstrates the degree of variation between opinions. The major groupings of the Birch-Marsden classification were used within which tumours were assigned for kappa analysis according to the clinical significance of the differential diagnoses. The mean agreement for all tumours together was 90%; kappa = 0.82, w kappa = 0.82. Retinoblastoma achieved the highest kappa value (1.0) and lymphoma the lowest (0.66). Of the cases, 16.5% had their original diagnoses amended and the panel confirmed the original diagnosis of paediatric pathologists in 89% of cases compared with 78% for general pathologists. The varying levels of agreement between experts confirm the difficulty of diagnosis in some tumour types, suggesting justification for specialist review in most diagnoses. Specialist training in paediatric pathology is also recommended.

Paediatric meningeal tumours

We review our experience of meningeal tumours in patients under 16 years who were treated between 1957 and 1993. These were 16 with meningiomas (median age 12 years) and 5 with poorly differentiated malignant meningeal tumours (median age 3 years). The incidence of meningeal tumours in this period was 1.62% of all CNS tumours. There were 19 supratentorial tumours (5 intraventricular), 1 tentorial and 1 cervical. Surgical excision was complete in 12 patients and incomplete in 6; in 2 patients a biopsy only was undertaken. The remaining patient had radiological diagnosis only. All 5 patients in the group with malignant poorly differentiated tumours died (median survival 5 months), confirming the aggressive nature of these lesions. Of the 16 patients with meningiomas, 4 died during followup but 11 of the 12 meningioma patients remaining alive had complete resections. There is a strong tendency for paediatric meningeal tumours to have a supratentorial origin and intraventricular location. The female preponderance found in adults is not evident in children. Incomplete surgical excision or focal neurological deficit at presentation was associated with poor outcome.

The long-term survivors

Recent research indicates that approximately 60% of children diagnosed with cancer in Britain are cured and as a result, about 1 in a 1000 of the general population will soon be survivors of childhood cancer. Unfortunately some elements of the therapies which are responsible for this remarkable success are associated with serious complications, sometimes decades after their administration. Therefore, a comprehensive knowledge of the risks and benefits of different therapies will only be obtained by monitoring the health of survivors indefinitely. With such therapeutic success, increasingly the composition of future treatment protocols will be influenced by knowledge of the risks of long term morbidity and mortality associated with past therapies. An awareness of the long term risks of complications of treatment is also important for estimating the future demand on the health services of this increasing proportion of the general population who together represent many life years of care. This chapter reviews what is known concerning the long term risks of complications of different treatments. Appropriate strategies for future clinical and epidemiological follow-up of the survivor population are discussed and the need for indefinite follow-up of the survivor population is emphasised.

Ifosfamide nephrotoxicity in children: histopathological features in two cases

We report on two children with rhabdomyosarcoma who received ifosfamide as part of their chemotherapy schedule. Both children subsequently developed severe ifosfamide-induced nephrotoxicity, necessitating electrolyte supplementation. We describe the histopathological findings of renal biopsies performed in these children after the onset of renal dysfunction and comment on the possible mechanisms involved in ifosfamide nephrotoxicity.

Treatment for children with brain tumours

The overall survival for children with malignant brain tumours has not greatly improved in recent years, so that apparently innovative treatments may seem attractive, especially in cases with a poor prognosis. Problems associated with treating such children include balancing the need to provide optimum treatment for individual patients with the need to properly evaluate advances in treatment in clinical trials and determining who should be responsible for decisions about funding such treatments. Treatment abroad is rarely justified when judged on the basis of whether the treatment is available in Britain (or European Community) and whether there is accepted evidence for its clinical benefit. However, referral to specialist paediatric centres is essential. The range of daily experience in such centres allows an educated choice between established and new treatments. Close collaboration between these centres is essential for clinical trials.

Clinical examination compared with anthropometry in evaluating nutritional status

Clinical assessments of nutritional status in a group of 44 inpatients, made by a panel of experienced childcare specialists, were compared with anthropometric assessments. Assessors were uniformly poor at detecting severe malnutrition and at assessing the nutritional status of infants. Nutritional status cannot be accurately assessed clinically and anthropometry is crucial.

Hyperaemia in rat neocortex produced by acute exposure to methylenedioxymethamphetamine

Cerebral blood flow and glucose utilization were measured in rat neocortex, hippocampus and striatum following methylenedioxymethamphetamine injection (5 mg/kg, i.v.), using the tracers [14C]iodoantipyrine and [14C]2-deoxyglucose, respectively. In control rats, blood flow was coupled to glucose metabolism, but in methylenedioxymethamphetamine-treated rats, marked hyperperfusion was measured in frontal and parietal cortex with no change in glucose use. This suggests that methylenedioxymethamphetamine has the potential to disrupt cerebrovascular control.

Spectrum of peritoneal mesothelioma in childhood: clinical and histopathologic features, including DNA cytometry

Different types of peritoneal mesothelioma (PM) occur in children and adults. All these share certain histopathologic features but differ in other aspects, such as age of occurrence, site and sex predominance, etiology, and biologic behavior. The article describes four patients, two with cystic PM (one of whom had multiple recurrences) and two with malignant PM (one of whom had pleural metastases). These cases illustrate the variable behavior of this tumor in childhood and highlight the difficulties encountered in diagnosis and treatment. Three different groups of mesothelioma are recognized: a classic, asbestos-related, malignant mesothelioma of adults, typically occurring in the pleural cavity; a multicystic mesothelioma, predominantly affecting the pelvic peritoneum of young women and associated with a good prognosis; and mesotheliomas in children, which are not associated with asbestos exposure and have an unpredictable biologic behavior requiring individual treatment strategies. In the patients studied, DNA index measured by flow cytometry showed a difference between the cystic (aneuploid) and malignant (diploid) tumors. The proliferative rate (S phase) of the tumor was low in all four cases.

DNA ploidy and proliferative activity (S-phase) in childhood soft-tissue sarcomas: their value as prognostic indicators

The value of DNA ploidy as a prognostic indicator is well established in many cancers, but recent studies in childhood rhabdomyosarcoma (RMS) have been contradictory. In a retrospective study of 128 cases of soft-tissue sarcoma (STS) diagnosed since 1980, the prognostic value of clinical, histological and flow cytometric parameters was compared, using univariate and multivariate methods. Eighty-one RMSs, 18 extraosseous Ewing's (EOE)/peripheral neuroectodermal tumours (PNETs) and 29 other non-RMS STSs were histologically and clinically reviewed. Five year actuarial survival was 63.4% for all STSs and 69.4% for RMSs. Paraffin-embedded tissue blocks were available for flow cytometry in 90 cases. Of the RMSs, 65.5% were aneuploid [DNA index (DI) > 1.1] compared with 23% of the EOE/PNETs and 31% of non-RMS STSs. Median S-phase was also significantly higher in RMSs (17.0%) than in other STSs (10.8%) (P = 0.0023). Univariate analysis in RMSs showed that stage, ploidy status, S-phase, site and tumour size all had a significant impact on survival. In multivariate analysis of 59 cases of RMS, one clinical and two flow cytometric parameters were independently associated with poor prognosis. These were stage (IV), nonhyperdiploidy (DI < 1.10 and > 1.8) and a high rate of proliferative activity (S-phase > 14.0%). These results confirm that ploidy and S-phase are important new prognostic indicators in rhabdomyosarcoma.

The mechanism of low testosterone levels in homozygous sickle-cell disease

Significantly lower testosterone levels are common in male patients with homozygous sickle-cell (SS) disease and have been attributed to either abnormalities of the hypothalamo-pituitary axis or primary testicular failure. The mechanism has now been investigated by observing the response to gonadotropin-thyrotropin releasing hormones (GnRH-TRH) in 10 male patients with SS disease and in 10 matched male sibling controls without sickle-cell disease. Mean basal levels of luteinizing hormone (LH), follicular stimulating hormone (FSH) and thyrotropin (TSH) were significantly elevated but prolactin (PRL) levels were within the normal range in the SS group. All hormones increased following GnRH-TRH, and proportionate increases over baseline were similar for FSH and TSH in SS and AA subjects, but SS patients showed a lesser percentage increase in LH at 30 minutes, and a higher percentage increase in PRL at 60 minutes. These observations are more consistent with primary testicular failure than with abnormalities of the hypothalamic-pituitary-testicular axis.

Neonatal tumours: a thirty-year population-based study

Estimates of the incidence and outcome of tumours in neonates are uncertain and most reports relate to selected experience in single centres. The definition of neonatal tumour is also unclear and histology is not always an accurate predictor of outcome. This report documents the incidence, clinical features, and outcome of neonatal tumours (birth-3 months) in a population-based paediatric register over a 30-year period from 1960-89. Case note and pathology review identified 170 cases for analysis, of which 21 were leukaemias, 14 CNS tumours, and 135 solid tumours of differing types. Fifty-eight percent were diagnosed in the first month and mature teratoma was the most common diagnosis (29%). Overall incidence increased over the period of the study. Important family medical history was identified in 16% of cases and 15% of patients had associated congenital abnormalities. Overall survival at 1 year was 55%, with leukaemia having the poorest prognosis. Treatment strategies must be individualised but many patients may have a better prognosis than expected and would benefit from assessment at a designated paediatric oncology centre.

Recurrent hemangiopericytoma of the chest wall: report of a case in a 5-year-old boy

Hemangiopericytoma in infants and children is usually benign. A case of recurrent hemangiopericytoma of the mediastinum in a 5-year-old boy is reported. The tumor recurred twice because of incomplete excision in the first instance. Immunohistochemistry of this enigmatic tumor is reviewed and ultrastructural features are described. The importance of total initial excision of the tumor and a prolonged follow-up is highlighted.

Carboplatin pharmacokinetics in children: the development of a pediatric dosing formula. The United Kingdom Children's Cancer Study Group

PURPOSE

The aim of this study was to define the pharmacokinetics of carboplatin in children and use the data to develop a pediatric dose formula. It was anticipated that renal function would be a major determinant of carboplatin disposition and the relationship between carboplatin clearance and glomerular filtration rate (GFR) was examined in detail.

PATIENTS AND METHODS

Plasma carboplatin pharmacokinetics were measured as ultrafiltrable platinum in 22 patients (5 to 63 kg) following 200 to 1,000 mg/m2 of carboplatin. GFR was measured by the plasma clearance of chromium 51-edathamil (51Cr-EDTA).

RESULTS

Carboplatin pharmacokinetics in children were best described in most patients (16 of 22) by a two-compartment model. The dose-normalized area under the plasma carboplatin concentration versus time curve (AUC) ranged from 3.1 to 9.6 mg/mL.min/400 mg/m2 and there was only a weak linear relationship between carboplatin dose and AUC (R2 = .31). There was a significant relationship between absolute carboplatin and 51Cr-EDTA clearances (R2 = .56), but the relationship was weaker (R2 = .28) when both clearances were normalized for body surface area. Carboplatin plasma clearance was predicted by the equation: clearance = GFR (mL/min) + 0.36 x body weight (BW; kg), and a modified form of the adult carboplatin dose formula is proposed: dose (mg) = target AUC x (GFR [mL/min] + [0.36 x BW(kg)]). Two further equations were developed that use the 51Cr-EDTA half-life (t1/2) to calculate the GFR and these may reduce errors resulting from inaccurate measurement of the volume of distribution for 51Cr-EDTA. In patients treated with single-agent carboplatin or carboplatin plus vincristine, there was a significant sigmoidal relationship between AUC and thrombocytopenia (R2 = .56).

CONCLUSION

GFR-based carboplatin dosing in children should be feasible and will be evaluated prospectively.

Retrospective study of prognostic value of DNA ploidy and proliferative activity in neuroblastoma

AIM

To assess the prognostic value of age and stage at diagnosis, site of primary tumour, cell ploidy and N-myc copy number in children with neuroblastoma.

METHODS

Flow cytometry was used to determine the cellular DNA content of paraffin wax embedded archival material from 69 cases of neuroblastoma and was successful in 52.

RESULTS

The age, stage, and survival distribution of the sampled cases was not significantly different from that in a larger population based series. There were seven diploid ("non-aneuploid") and 45 aneuploid (including two tetraploid and four triploid) tumours. The 10 year survival was significantly better for cases of aneuploid rather than diploid tumours (p < 0.05). An important new finding was that 10 year survival was also significantly better for tumours with a low percentage of cells in S phase (p < 0.03).

CONCLUSION

The percentage of cells in S phase, a measure of the proliferative activity of the tumour, correlated with prognosis in neuroblastoma. This should be measured with other biological features of the disease, such as N-myc copy number, when prognostic indicators are being assessed.

Treatment of childhood acute myeloid leukaemia using the BFM-83 protocol

Thirty children presenting with acute nonlymphoblastic leukaemia from June 1984 to December 1989 were treated at one UK centre using a West German protocol, AML-BFM-83. This consisted of Induction, an intensive outpatient-based Consolidation regimen with seven different drugs and cranial irradiation, and Continuation therapy with thioguanine and cytosine arabinoside for 2 years with additional Adriamycin in the first year. Twenty-five children achieved complete remission (83%). There were two early deaths from haemorrhage and infection and three from Induction failure. After a median follow-up time of 60 months, nine relapses have occurred, all in the bone marrow. Life table analysis revealed a probability for survival at 5 years of 47%, event-free survival 43%, and event-free interval 50%. Median bed occupancy for chemotherapy and toxicity was 41 days, with median hospital stays of 29 days for Induction, 11 days for Consolidation and less than 1 day for Continuation. This data suggests that long-term remissions can be achieved in just under half of children with acute nonlymphoblastic leukaemia while creating only modest demands on inpatient resources.

21-day schedule oral etoposide in children--a feasibility study

To determine the feasibility and toxicity of prolonged oral etoposide in children, 22 patients with relapsed or refractory disease were commenced on etoposide 50-100 mgs/m2 per day for 21 days. A second course was administered after full blood count recovery, followed by disease reassessment. In total, 72 courses were evaluable for toxicity, with 10% of completed courses complicated by febrile neutropenia. 15 patients were evaluable for response, with 1 partial response, 10 stable disease and 4 progressive disease. This schedule was well tolerated with acceptable toxicity when doses of less than 80 mg/m2/day were administered and warrants further evaluation.

Incidence and etiology of ifosfamide nephrotoxicity: report of a meeting held in Rhodes, Greece, October 3, 1991, sponsored by Asta Medica, Frankfurt, Germany

The nephrotoxic potential of ifosfamide is now clearly recognized but the true incidence is unknown and risk factors are uncertain. There are, as yet, few studies which systemically explore these issues although many centers have collected data from patients receiving ifosfamide. These support the need for collaborative studies to look at the influence of probable risk factors such as age, cumulative/dose, schedule, and exposure to other nephrotoxic drugs. The ability to detect acute subclinical changes in renal function may provide the opportunity to predict subsequent clinical toxicity. The consensus of opinion recorded so far provides the basis of recommendations for future studies.

Neuroblastoma: a 32-year population-based study--implications for screening

This paper describes a retrospective population-based study of neuroblastoma in the West Midlands Health Authority Region--childhood population 1.12 million (OPCS, census 1981)--in which 239 cases were diagnosed between 1st January 1957 and 31st December 1988. The age standardised rate of tumour incidence has remained constant at 7.2 cases per million children per year. The median age at diagnosis was 2 years with 18% of children presenting before the age of 6 months. Fifty children (21%) presented before the age of one year, and for this group of children, the prognosis has improved significantly over the 32-year period (10 year survival increasing from 63% in 1957-67 to 87% in 1978-88), whereas for the 189 (79%) children who presented after one year of age, the prognosis has remained very poor during the study period (10 year survival 1957-67 = 9.5%, 1978-88 = 8.5%). This study supports the need for a prospective study of mass screening at several intervals rather than only at 6 months of age.