Gold nanoparticles are emerging as promising agents for cancer therapy and are being investigated as drug carriers, photothermal agents, contrast agents and radiosensitisers. This review introduces the field of nanotechnology with a focus on recent gold nanoparticle research which has led to early-phase clinical trials. In particular, the pre-clinical evidence for gold nanoparticles as sensitisers with ionising radiation in vitro and in vivo at kilovoltage and megavoltage energies is discussed.
Positron emission tomography (PET)/CT scans can improve target definition in radiotherapy for non-small cell lung cancer (NSCLC). As staging PET/CT scans are increasingly available, we evaluated different methods for co-registration of staging PET/CT data to radiotherapy simulation (RTP) scans.
10 patients underwent staging PET/CT followed by RTP PET/CT. On both scans, gross tumour volumes (GTVs) were delineated using CT (GTVCT) and PET display settings. Four PET-based contours (manual delineation, two threshold methods and a source-to-background ratio method) were delineated. The CT component of the staging scan was co-registered using both rigid and deformable techniques to the CT component of RTP PET/CT. Subsequently rigid registration and deformation warps were used to transfer PET and CT contours from the staging scan to the RTP scan. Dice's similarity coefficient (DSC) was used to assess the registration accuracy of staging-based GTVs following both registration methods with the GTVs delineated on the RTP PET/CT scan.
When the GTVCT delineated on the staging scan after both rigid registration and deformation was compared with the GTVCTon the RTP scan, a significant improvement in overlap (registration) using deformation was observed (mean DSC 0.66 for rigid registration and 0.82 for deformable registration, p = 0.008). A similar comparison for PET contours revealed no significant improvement in overlap with the use of deformable registration.
No consistent improvements in similarity measures were observed when deformable registration was used for transferring PET-based contours from a staging PET/CT. This suggests that currently the use of rigid registration remains the most appropriate method for RTP in NSCLC.
Consistency in target organ and organ at risk position from planning to treatment is an important basic principle of radiotherapy. This study evaluates the effectiveness of bladder-filling instructions in achieving a consistent and reproducible bladder volume at the time of planning CT and daily during the course of radical radiotherapy for prostate cancer. It also assessed the rate of bladder filling before and at the end of radiotherapy.
30 men attending for radiation therapy planning for prostate cancer received written and verbal bladder-filling instructions. They had their bladder volume assessed using a bladder ultrasound scanner post-void, immediately prior to planning CT scan and then daily immediately prior to treatment while in the therapy position. The inflow was calculated using the void and full bladder volumes and the time for the bladder to fill.
The mean bladder volume at the time of planning was 282 ml (range 89–608 ml, standard deviation (SD) = 144.5 ml). This fell during treatment, with a mean value for all treatments of 189 ml (range 11–781 ml, SD = 134 ml). During radiotherapy, 76% (828/1090), 53% (579/1090) and 36% (393/1090) of bladder volumes had >50 ml, >100 ml and >150 ml difference, respectively when compared with their volume at the time of planning. Inflow reduced from 4.6 ml min–1, SD = 2.9 min–1 at planning to 2.5 min–1, SD = 1.8 min–1 after radiotherapy.
The Bladderscan device (BVI 6400 Bladderscan, Verathon Medical UK, Sandford, UK) provides an effective means of assessing bladder volume prior to radiotherapy for prostate cancer. The evaluated bladder-filling protocol does not produce consistent, reproducible bladder volumes for radiotherapy.
To improve the integration of MRI with radiotherapy treatment planning, our department fabricated a flat couch top for our MR scanner. Setting up using this couch top meant that the patients were physically higher up in the scanner and, posteriorly, a gap was introduced between the patient and radiofrequency coil.
Phantom measurements were performed to assess the quantitative impact on image quality. A phantom was set up with and without the flat couch insert in place, and measurements of image uniformity and signal to noise were made. To assess clinical impact, six patients with pelvic cancer were recruited and scanned on both couch types. The image quality of pairs of scans was assessed by two consultant radiologists.
The use of the flat couch insert led to a drop in image signal to noise of approximately 14%. Uniformity in the anteroposterior direction was affected the most, with little change in right-to-left and feet-to-head directions. All six patients were successfully scanned on the flat couch, although one patient had to be positioned with their arms by their sides. The image quality scores showed no statistically significant change between scans with and without the flat couch in place.
Although the quantitative performance of the coil is affected by the integration of a flat couch top, there is no discernible deterioration of diagnostic image quality, as assessed by two consultant radiologists. Although the flat couch insert moved patients higher in the bore of the scanner, all patients in the study were successfully scanned.
Aims. To compare methylation profiles, protein expression, and microsatellite instability (MSI) of sporadic, HNPCC, and familial hyperplastic polyps (HPs). Methods. Methylation-specific PCR (MSP) and pyrosequencing assessed p16, MGMT, hMLH-1, MINT 1, and MINT 31 methylation. IHC (Immunohistochemistry) assessed Ki67, CK20, hMLH-1, hMSH-2, and hMSH-6 protein expression. MSI analysis was performed on those polyps with adequate DNA remaining. Results. 124 HPs were identified 78 sporadic, 21 HNPCC, 25 familial, and
the HNPCC group demonstrated no significant differences in overall methylation (P = .186 Chi2). The familial group demonstrated significantly less over all methylation levels (P = .004 Chi2). Conclusions. HPs that occur in HNPCC have no more worrying features at a molecular level than those patients with HPs in a sporadic setting.
The mitotic arrest deficiency protein 2 (MAD2) is a key component of the mitotic spindle assembly checkpoint, monitoring accurate chromosomal alignment at the metaphase plate before mitosis. MAD2 also has a function in cellular senescence and in a cell's response to microtubule inhibitory (MI) chemotherapy exemplified by paclitaxel.
Using an siRNA approach, the impact of MAD2 down-regulation on cellular senescence and paclitaxel responsiveness was investigated. The endpoints of senescence, cell viability, migration, cytokine expression, cell cycle analysis and anaphase bridge scoring were carried out using standard approaches.
We show that MAD2 down-regulation induces premature senescence in the MCF7 breast epithelial cancer cell line. These MAD2-depleted (MAD2↓) cells are also significantly replicative incompetent but retain viability. Moreover, they show significantly higher levels of anaphase bridges and polyploidy compared to controls. In addition, these cells secrete higher levels of IL-6 and IL-8 representing key components of the senescence-associated secretory phenotype (SASP) with the ability to impact on neighbouring cells. In support of this, MAD2↓ cells show enhanced migratory ability. At 72 h after paclitaxel, MAD2↓ cells show a significant further induction of senescence compared with paclitaxel naive controls. In addition, there are significantly more viable cells in the MAD2↓ MCF7 cell line after paclitaxel reflecting the observed increase in senescence.
Considering that paclitaxel targets actively dividing cells, these senescent cells will evade cytotoxic kill. In conclusion, compromised MAD2 levels induce a population of senescent cells resistant to paclitaxel.
mitotic assembly deficient protein 2 (MAD2); cellular senescence; paclitaxel resistance; breast cancer
Hypoxia is a microenvironmental feature in the inflamed joint, which promotes survival advantage for cells. The aim of this study was to examine the relationship of partial oxygen pressure in the synovial tissue (tPO2) in patients with inflammatory arthritis with macroscopic/microscopic inflammation and local levels of proinflammatory mediators.
Patients with inflammatory arthritis underwent full clinical assessment and video arthroscopy to quantify macroscopic synovitis and measure synovial tPO2 under direct visualisation. Cell specific markers (CD3 (T cells), CD68 (macrophages), Ki67 (cell proliferation) and terminal deoxynucleotidyl transferase dUTP nick end labelling (cell apoptosis)) were quantified by immunohistology. In vitro migration was assessed in primary and normal synoviocytes (synovial fibroblast cells (SFCs)) using a wound repair scratch assay. Levels of tumour necrosis factor α (TNFα), interleukin 1β (IL1β), interferon γ (IFNγ), IL6, macrophage inflammatory protein 3α (MIP3α) and IL8 were quantified, in matched serum and synovial fluid, by multiplex cytokine assay and ELISA.
The tPO2 was 22.5 (range 3.2–54.1) mm Hg and correlated inversely with macroscopic synovitis (r=−0.421, p=0.02), sublining CD3 cells (−0.611, p<0.01) and sublining CD68 cells (r=−0.615, p<0.001). No relationship with cell proliferation or apoptosis was found. Primary and normal SFCs exposed to 1% and 3% oxygen (reflecting the median tPO2 in vivo) induced cell migration. This was coupled with significantly higher levels of synovial fluid tumour necrosis factor α (TNFα), IL1β, IFNγ and MIP3α in patients with tPO2 <20 mm Hg (all p values <0.05).
This is the first study to show a direct in vivo correlation between synovial tPO2, inflammation and cell migration, thus it is proposed that hypoxia is a possible primary driver of inflammatory processes in the arthritic joint.
Oxidative DNA damage results from DNA adducts such as 8-oxo-7, 8 dihydro-2′-deoxyguanosine (8-oxo-dG), which is a pro-mutagenic lesion. No known association between 8-oxo-dG, disease progression and survival exists in colorectal cancer (CRC). We examined levels of 8-oxo-dG in sporadic CRC to determine its relationship with pathological stage and outcome. A total of 143 CRC patients and 105 non-cancer patients were studied. Nuclear and cytoplasmic 8-oxo-dG was assessed using immunohistochemistry. Double immunofluorescence using 8-oxo-dG and manganese superoxide dismutase (MnSOD) antibodies localised cytoplasmic 8-oxo-dG. Apoptosis was detected using TUNEL. Nuclear staining levels were similar in tumour tissue and matched normal mucosa in both epithelial (P=0.22) and stromal (P=0.85) cells. Epithelial cytoplasmic staining was greater in tumour tissue (P<0.001). Double immunofluorescence localised cytoplasmic 8-oxo-dG to mitochondria. Epithelial and stromal nuclear 8-oxo-dG decreased with local disease spread, but highest levels were found in distant disease (P<0.01). Survival was related to epithelial nuclear and stromal staining in normal mucosa (P<0.001) and tumour (P<0.01) but was unrelated to cytoplasmic staining. Normal control cells in tissue from cancer patients with high levels of 8-oxo-dG failed to undergo cell death. 8-oxo-dG may be an important biomarker of disease risk, progression and survival for CRC patients.
8-oxo-dG; oxidative damage; colon; mitochondria; survival; apoptosis
We sought to characterise whether dexamethasone (DEX) may enhance tumour response to docetaxel in in vitro and in vivo models of metastatic prostate cancer (CaP). In vitro experiments conducted on PC3 and human bone marrow endothelial cells (hBMECs) determined that administration of DEX (10 nM) reduced constitutive nuclear factor-κB (NF-κB) activity, decreasing interleukin (IL)-8, CXCL1 and VEGF gene expression in PC3 cells. Dexamethasone also attenuated docetaxel-induced NF-κB and activator protein-1 transcription and reduced docetaxel-promoted expression/secretion of IL-8 and CXCL1 in PC3 and hBMECs. Although DEX failed to enhance docetaxel cytotoxicity on PC3 cells, DEX potentiated the antiangiogenic activity of docetaxel in vitro, further reducing vessel area and vessel length in developing endothelial tubes (P<0.05). Docetaxel had a potent antiangiogenic activity in the dorsal skin flap-implanted PC3 tumours in vivo. Small blood vessel formation was further suppressed in tumours co-treated with docetaxel and DEX, substantiated by an increased average vessel diameter and segment length and a decreased number of branch points in the residual tumour vasculature (P<0.001). Our data show that DEX potentiates the antiangiogenic activity of docetaxel, suggesting a putative mechanism for the palliative and survival benefits of these agents in metastatic CaP.
dexamethasone; docetaxel; angiogenesis; prostate cancer
Costello syndrome (CS) is a rare multiple congenital abnormality syndrome, associated with failure to thrive and developmental delay. One of the more distinctive features in childhood is the development of facial warts, often nasolabial and in other moist body surfaces. Individuals with CS have an increased risk of malignancy, suggested to be about 17%. Recently, mutations in the HRAS gene on chromosome 11p13.3 have been found to cause CS.
We report here the results of HRAS analysis in 43 individuals with a clinical diagnosis of CS.
Mutations were found in 37 (86%) of patients. Analysis of parental DNA samples was possible in 16 cases for both parents and in three cases for one parent, and confirmed the mutations as de novo in all of these cases. Three novel mutations (G12C, G12E, and K117R) were found in five cases.
These results confirm that CS is caused, in most cases, by heterozygous missense mutations in the proto‐oncogene HRAS. Analysis of the major phenotypic features by mutation suggests a potential correlation between malignancy risk and genotype, which is highest for patients with an uncommon (G12A) substitution. These results confirm that mutation testing for HRAS is a reliable diagnostic test for CS.
HRAS mutations; malignancy
Aims: To establish the frequency and risk factors for visual loss in a primary referral cohort of hospital patients with uveitis.
Methods: 561 consecutive uveitis patients attending three district hospitals were recruited and the acuity at the end of the study period recorded. A retrospective case-control study of risk factors for visual loss (permanent loss of acuity <6/9) was performed. Risk factors examined included type of uveitis, age at onset of uveitis, race, type of systemic inflammatory disease, length of follow up, and treatment variables.
Results: Visual loss of at least 6/12 in one eye was found in 111 patients (19.9%). Only four patients (0.7%) suffered severe bilateral visual loss (6/36 or less). Visual loss was associated with age at onset >60 years (odds ratio 3.9, 95% confidence interval (CI) 2.2 to 7.0, long follow up 2.0 (1.2 to 3.3) and a history of cataract surgery 3.9 (2.1 to 7.2). It was less likely in patients with acute anterior uveitis 0.2 (0.1 to 0.3).
Conclusion: The frequency of visual loss associated with uveitis in a district hospital cohort is less than that found in referral centres and levels of legal blindness are low. Although acute anterior uveitis has a low frequency of visual loss it contributes significantly to the total burden. The ocular co-morbidity of the elderly may contribute to the increased visual loss of late onset uveitis.
uveitis; age; visual loss; epidemiology
pulmonary hypertension; septostomy; survival
Objective: To study the prevalence of hypertension in a cohort of patients using the current strategy of repair in early childhood.
Patients: The cohort of patients with coarctation of the aorta born between 1983 and 1992.
Intervention: Casual (mean of three resting readings) and 24 hour blood pressure were measured in 119 children and compared with data from 1034 normal controls. The arch repair and left ventricular parameters were assessed using Doppler echocardiography.
Results: Median ages at first intervention and at blood pressure measurement were 0.2 years (interquartile range 0.04–2.0) and 12.0 years (9.0–14.5), respectively. Doppler velocity in the descending aorta was significantly associated with blood pressure (r = 0.28, p = 0.002 for casual systolic blood pressure (SBP); r = 0.26, p = 0.005 for mean 24 hour SBP). Patients were classified as having “no” (n = 70) or “mild” (n = 49) arch obstruction. Casual SBP was > 95th centile in 28% (34 of 119) overall and in 21% (15 of 70) of the no arch obstruction group. Mean 24 hour SBP was > 95th centile in 30% (36 of 119) overall and in 19% (13 of 70) of the no obstruction group. The sensitivity and specificity of casual SBP in detecting increased 24 hour SBP were 66% and 88%, respectively.
Conclusions: This unique study of a large cohort of patients treated for coarctation in early childhood showed that a disappointingly high prevalence of hypertension is already apparent in children aged 7–16 years in the absence of significant arch obstruction, whether assessed by 24 hour or by casual blood pressure measurement.
blood pressure; coarctation of the aorta; hypertension
Background: Although severe T cell immunodeficiency in DiGeorge anomaly is rare, previous studies of humoral function in these patients have found no antibody abnormalities but have not examined the response to polysaccharide antigens. Isolated cases of autoimmunity have been reported. Several patients with 22q11.2 deletion attending our immunology clinic suffered recurrent sinopulmonary infection or autoimmune phenomena.
Aims: To investigate humoral immunodeficiency, particularly pneumococcal polysaccharide antibody deficiency, and autoimmune phenomena in a cohort of patients with 22q11.2 deletion.
Methods: A history of severe or recurrent infection and autoimmune symptoms were noted. Lymphocyte subsets, immunoglobulins, IgG subclasses, specific vaccine antibodies, and autoantibodies were measured. Subjects were vaccinated with appropriate antigens as indicated.
Results: Of 32 patients identified, 26 (81%) had severe or recurrent infection, of which 13 (50%) had abnormal serum immunoglobulin measurements and 11/20 ≥4 years old (55%) had an abnormal response to pneumococcal polysaccharide. Ten of 30 patients (33%) had autoimmune phenomena; six (20%) were symptomatic.
Conclusions: Humoral immunodeficiency is more common than previously recognised in patients with 22q11.2 deletion. Normal T cell function and immunoglobulin levels do not exclude poor specific antibody responses. Patients should be referred for formal immunological assessment of cellular and humoral immune function.
OBJECTIVE—To predict the growth in demand for long term follow up of adults with congenital heart disease.
DESIGN—Observed diagnoses of congenital heart disease in infancy and childhood were adjusted for observed infant survival, predicted further survival to age 16 years, underascertainment in older childhood, and predicted need for long term follow up.
SETTING—The resident population of one health region in the UK.
PATIENTS—All confirmed cardiovascular malformations diagnosed in 1985 to 1999 in children born in 1985 to 1994.
RESULTS—1942 cases of congenital heart disease were diagnosed in infancy in a population of 377 310 live births (5.2/1000). 1588 (82%) survived to 1 year and 1514 were predicted to survive to age 16. 605 further diagnoses were made in childhood—678 when adjusted for underascertainment. Thus, 2192 children were predicted to reach age 16, of whom 784 would require long term follow up in adult life. The adult population would comprise 28% complex, 54% significant, and 18% minor congenital heart disease. These figures predict the need for adult follow up of congenital heart disease of over 200 extra cases per 100 000 live births each year or over 1600 extra cases a year every year in the UK.
CONCLUSIONS—The need for follow up of congenital heart disease in adult life is likely to grow linearly, with increasing complexity and increasing need for reinvestigation and reintervention with time. Appropriate provision should be made for adequate manpower, resources, and facilities for care of these patients.
Keywords: adult congenital heart disease; resources; patient survival
OBJECTIVES—To investigate a reported cluster of Down's syndrome in offspring of former pupils of a girls' school in Ireland, to establish the prevalence of Down's syndrome among live births in the area around the school, and to review the literature on the possible causes of reported clusters of Down's syndrome.
METHODS—Questionnaire survey of obstetric and personal histories of women who had attended the girls' school at Dundalk, County Louth, Republic of Ireland, at some time during 1956-7, and also of women who had attended another, nearby, girls' school during the same period. Comparison of observed numbers of cases of Down's syndrome identified by these surveys with maternal age adjusted expected numbers for the reported live births. Laboratory tests were conducted to verify and characterise the cases of Down's syndrome constituting the cluster. Retrospective collection and collation of data on Down's syndrome occurring among live births, and the compilation of maternal age specific incidences, in County Louth and in Newry and Mourne District in neighbouring Northern Ireland, during 1961-80. These rates were compared with reference rates and rates for other areas of Ireland.
RESULTS—Six children with Down's syndrome were confirmed among 387 reported live births to women who had been pupils at the girls' school in Dundalk during 1956-7, compared with 0.69 expected (nominal p<10-4). Five of the affected births were to mothers under 30 years of age, against 0.15 expected (nominal p<10-6), although only four of these mothers were attending the school at any one time. The origin of the non-disjunction was found to be maternal first meiotic in four children, mitotic after fertilisation in another (with the youngest mother), and in the remaining one could not be determined. The marked excess of Down's syndrome in births to young mothers did not extend to offspring of former pupils of the other Dundalk girls' school surveyed, or to live births in County Louth generally or in adjacent Newry and Mourne District.
CONCLUSION—A striking, highly localised, excess of Down's syndrome in births to young mothers who had attended a girls' school in Dundalk during 1956-57 has been confirmed. However, not all of the mothers of the affected children attended the school concurrently and the origin of non-disjunction in one child was an error occurring after conception. Some exposure essentially confined to girls attending the school at this time is a possible, although unlikely, explanation, but a review of potential risk factors does not suggest what this could be. Previous suggestions that an influenza epidemic or contamination from the Windscale nuclear reactor fire might be implicated, both of which occurred in October 1957, can be effectively dismissed because three of the women with affected offspring had left the school by then and had moved away from Dundalk, and Down's syndrome in the child of another mother originated in an error after fertilisation. Owing to the retrospective nature of the investigation and the characteristics of the cases, chance is the most likely explanation for the cluster.
Keywords: Down's syndrome; cluster; maternal exposure
OBJECTIVE—To investigate mortality, cause of death, survival, and quality of life in all types of cardiac malformation with congenital pulmonary atresia.
SETTING—The resident population of one health region with a single tertiary referral centre.
PATIENTS—All babies with pulmonary atresia live born in 1980 to 1995.
MAIN OUTCOME MEASURES—Anatomical classification, total mortality, cause of death, duration of survival, exercise ability. All cases were classified as pulmonary atresia with intact septum (PA-IVS), pulmonary atresia with ventricular septal defect (PA-VSD), or pulmonary atresia with complex cardiac malformation (complex pulmonary atresia).
RESULTS—129 cardiac malformations with congenital pulmonary atresia were identified from 601 635 live births (21.4/100 000): 29 had PA-IVS, 60 had PA-VSD, and 40 had complex pulmonary atresia. Total mortality was 72/129 (56%), with 15 deaths in the first week and 49 in the first year. There were 23 surgical deaths, 33 hospital deaths (not related to surgery), and 16 sudden deaths, 12 of which remained unexplained. The sudden death rate was 29/1000 patient years of follow up. Of the 57 survivors, 39% have exercise ability I or II and 61% III or IV. Definitive surgical repair produced better exercise ability.
CONCLUSIONS—Early mortality is high in all types of pulmonary atresia, although survival has improved in recent years. Most children who have not undergone definitive repair have significant exercise limitation.
Keywords: congenital heart disease; pulmonary atresia; sudden death; quality of life
We tested the feasibility and toxicity of high activities Rhenium-186 hydroxyethylidene diphosphonate, with peripheral blood stem cell rescue in patients with progressive hormone refractory prostate cancer metastatic to bone. Twenty-five patients received between 2500 and 5000 MBq of Rhenium-186 hydroxyethylidene diphosphonate followed 14 days later by the return of peripheral blood peripheral blood stem cells. Activity limiting toxicity was defined as grade III haematological toxicity, lasting at least 7 days, or grade IV haematological toxicity of any duration or any serious unexpected toxicity. Activity limiting toxicity occurred in two of six who received activities of 5000 MBq and maximum tolerated activity was defined at this activity level. Prostate specific antigen reductions of 50% or more lasting at least 4 weeks were seen in five of the 25 patients (20%) all of whom received more than 3500 MBq of Rhenium-186 hydroxyethylidene diphosphonate. The actuarial survival at 1 year is 54%. Administered activities of 5000 MBq of Rhenium-186 hydroxyethylidene diphosphonate are feasible using autologous peripheral blood peripheral blood stem cell rescue in patients with progressive hormone refractory prostate cancer metastatic to bone. The main toxicity is thrombocytopaenia, which is short lasting. A statistically significant activity/prostate specific antigen response was seen. We have now commenced a Phase II trial to further evaluate response rates.
British Journal of Cancer (2002) 86, 1715–1720. doi:10.1038/sj.bjc.6600348 www.bjcancer.com
© 2002 Cancer Research UK
prostate cancer; hormone refractory; radionuclide therapy; peripheral blood peripheral blood stem cell support; rhenium-186 HEDP; palliation; bone metastases
OBJECTIVE—To identify the incidence, causes, and characteristics of sudden death at age 1-20 years.
DESIGN—A review of all deaths at age 1-20 years. Death certificates were obtained from the Office for National Statistics, and further information, where appropriate, from coroners, paediatricians, physicians, and pathologists.
SETTING—The resident population of one English health region in 1985-1994.
RESULTS—In a population of 806 500 children and adolescents aged 1-20 years there were 2523 deaths in 10 years. Medical causes accounted for 1017 deaths (40%); 1236 (49%) were unnatural, and 270 (11%) were sudden. These sudden deaths comprised 142 with a previous diagnosis, the commonest being epilepsy 49 (34%), cardiovascular disease 33 (23%), and asthma 30 (21%); 87 attributed to a cause discovered at necropsy, which was respiratory infection in 32 (37%), other infections in 17 (20%), and unsuspected cardiovascular abnormalities in 26 (30%); 41 remained unexplained.
CONCLUSIONS—Half of all sudden deaths in children or adolescents were attributed to an already diagnosed condition. Abnormalities identified at necropsy accounted for one third of sudden deaths. Undiagnosed hypertrophic cardiomyopathy caused less than one death per million person years in the population aged 1-20 years. Unexplained sudden death, which may be caused by primary cardiac arrhythmia, is probably about 10 times more common.
Keywords: sudden death; necropsy; paediatric cardiology