EXPERIENCES IN DEVELOPING A NATIONAL DOSE REGISTER IN FINLAND AND MERGING IT WITH THE OVERALL SUPERVISORY DATA SYSTEM

In recent years, a new national Dose Register has been under development in Finland. This article presents this work, the challenges in the project, the features of the new register and experiences in using it. There were several motivations for creating a new register. The technical implementation of the existing Dose Register needed to be reformed, and there was also a need to improve electronic communication and access to the recorded data. The development was challenging and took more time and effort than expected. Despite the challenges, the new system works quite reliably and enables the use of the registered data to more easily improve radiation safety.

INVESTIGATIONS CONDUCTED AMONG FINNISH RADIATION WORKERS IN 2004-13 AND THEIR EFFECT ON THE RECORDED INDIVIDUAL DOSES

Investigations are sometimes required to verify dose assessments or, where the reliability of the original results is known to be in question, to replace them with an estimate of the dose. In Finland, such investigations are conducted by three different parties: the Radiation and Nuclear Safety Authority (STUK), the individual monitoring service (IMS) and the parties operating a radiation practice (the undertakings). The reasons for such investigations as well as the findings from them vary widely between different parties. To determine their usefulness, all investigations carried out on Finnish radiation workers by the STUK, the IMS and the undertakings during 2004-13 have been reviewed. This paper presents the number, reasons for and findings of these investigations. The effect of the investigations on the recorded individual doses as well as on the working methods and other aspects of radiation protection in the work environment are described.

Dynamic Imaging of Pulmonary Ventilation in Children Using Digital Subtraction Radiography

Digital subtraction radiography is a sensitive method for imaging changes in pulmonary aeration during the respiratory cycle. The findings of 75 consecutive dynamic pulmonary examinations performed on 49 pediatric patients using this technique were reviewed together with the findings at chest radiography and, in 18 cases, with bronchoscopy. Symmetric diaphragmatic movement and synchronous, homogeneous variation in the attenuation of lung parenchyma indicated normal conditions in 9 (18%) patients. The most common abnormal finding (36 patients) was an asynchronous variation in the attenuation of the lung parenchyma. A greatly diminished or absent variation in attenuation was diagnostic for a serious air passage obstruction in 7 children. Other abnormal findings were a lowered amplitude of diaphragmatic movement, asynchronous diaphragmatic movement and mediastinal shift. In 10 patients (20%) the dynamic study showed parenchymal abnormalities when chest radiography was normal. Bronchoscopy was performed in 4 of these 10 patients and showed abnormalities in each case.

Dynamic Imaging of Pulmonary Ventilation

A new fluoroscopic imaging device consisting of an AT-micro-computer and a digital image memory unit has been used in experimental and clinical ventilation studies during a 2-year period. Digital images with 256 shades of gray were collected during one to 3 ventilation cycles at the rate of 6 to 25 images/s and stored on an optical laser disc. Both subtracted time interval difference (TID-) images and images relative, for example, to the mean image of the cycle (REL-images) were produced. The series of images could also be evaluated dynamically using animation sequences or analyzed using region of interest calculations. The method gave dynamic information with adequate spatial resolution and was easy to use in clinical practice. The radiation dose was kept low due to the high kilovoltage and heavy beam filtration technique. In experimental studies the software enabled flexible measurements of physiological pulmonary parameters.

Assessment of targeted and non-targeted responses in cells deficient in ATM function following exposure to low and high dose X-rays

Radiation sensitivity at low and high dose exposure to X-rays was investigated by means of chromosomal aberration (CA) analysis in heterozygous ATM mutation carrier and A-T patient (biallelic ATM mutation) lymphoblastoid cell lines (LCLs). Targeted and non-targeted responses to acutely delivered irradiation were examined by applying a co-culture system that enables study of both directly irradiated cells and medium-mediated bystander effects in the same experimental setting. No indication of radiation hypersensitivity was observed at doses of 0.01 Gy or 0.1 Gy for the ATM mutation carrier LCL. The A-T patient cells also did not show low-dose response. There was significant increase in unstable CA yields for both ATM mutation carrier and A-T LCLs at 1 and 2 Gy, the A-T cells displaying more distinct dose dependency. Both chromosome and chromatid type aberrations were induced at an increased rate in the irradiated A-T cells, whereas for ATM carrier cells, only unstable chromosomal aberrations were increased above the level observed in the wild type cell line. No bystander effect could be demonstrated in any of the cell lines or doses applied. Characteristics typical for the A-T cell line were detected, i.e., high baseline frequency of CA that increased with dose. In addition, dose-dependent loss of cell viability was observed. In conclusion, CA analysis did not demonstrate low-dose (≤100 mGy) radiosensitivity in ATM mutation carrier cells or A-T patient cells. However, both cell lines showed increased radiosensitivity at high dose exposure.

Loss of SUFU function in familial multiple meningioma

Meningiomas are the most common primary tumors of the CNS and account for up to 30% of all CNS tumors. An increased risk of meningiomas has been associated with certain tumor-susceptibility syndromes, especially neurofibromatosis type II, but no gene defects predisposing to isolated familial meningiomas have thus far been identified. Here, we report on a family of five meningioma-affected siblings, four of whom have multiple tumors. No NF2 mutations were identified in the germline or tumors. We combined genome-wide linkage analysis and exome sequencing, and we identified in suppressor of fused homolog (Drosophila), SUFU, a c.367C>T (p.Arg123Cys) mutation segregating with the meningiomas in the family. The variation was not present in healthy controls, and all seven meningiomas analyzed displayed loss of the wild-type allele according to the classic two-hit model for tumor-suppressor genes. In silico modeling predicted the variant to affect the tertiary structure of the protein, and functional analyses showed that the activity of the altered SUFU was significantly reduced and therefore led to dysregulated hedgehog (Hh) signaling. SUFU is a known tumor-suppressor gene previously associated with childhood medulloblastoma predisposition. Our genetic and functional analyses indicate that germline mutations in SUFU also predispose to meningiomas, particularly to multiple meningiomas. It is possible that other genic mutations resulting in aberrant activation of the Hh pathway might underlie meningioma predisposition in families with an unknown etiology.

A comprehensive study of the association between the EGFR and ERBB2 genes and glioma risk

Glioma is the most common type of adult brain tumor and glioblastoma, its most aggressive form, has a dismal prognosis. Receptor tyrosine kinases such as the epidermal growth factor receptor (EGFR, ERBB2, ERBB3, ERBB4) family, and the vascular endothelial growth factor receptor (VEGFR), play a central role in tumor progression. We investigated the genetic variants of EGFR, ERBB2, VEGFR and their ligands, EGF and VEGF on glioma and glioblastoma risk. In addition, we evaluated the association of genetic variants of a newly discovered family of genes known to interact with EGFR: LRIG2 and LRIG3 with glioma and glioblastoma risk. Methods. We analyzed 191 tag single nucleotide polymorphisms (SNPs) capturing all common genetic variation of EGF, EGFR, ERBB2, LRIG2, LRIG3, VEGF and VEGFR2 genes. Material from four case-control studies with 725 glioma patients (329 of who were glioblastoma patients) and their 1 610 controls was used. Haplotype analyses were conducted using SAS/Genetics software. Results. Fourteen of the SNPs were significantly associated with glioma risk at p< 0.05, and 17 of the SNPs were significantly associated with glioblastoma risk at p< 0.05. In addition, we found that one EGFR haplotype was related to increased glioblastoma risk at p=0.009, Odds Ratio [OR] = 1.67 (95% confidence interval (CI): 1.14, 2.45). The Bonferroni correction made all p-values non-significant. One SNP, rs4947986 next to the intron/exon boundary of exon 7 in EGFR, was validated in an independent data set of 713 glioblastoma and 2 236 controls, [OR] = 1.42 (95% CI: 1.06,1.91). Discussion. Previous studies show that regulation of the EGFR pathway plays a role in glioma progression but the present study is the first to find that certain genotypes of the EGFR gene may be related to glioblastoma risk. Further studies are required to reinvestigate these findings and evaluate the functional significance.

Interaction between 5 genetic variants and allergy in glioma risk

The etiology of glioma is barely known. Epidemiologic studies have provided evidence for an inverse relation between glioma risk and allergic disease. Genome-wide association data have identified common genetic variants at 5p15.33 (rs2736100, TERT), 8q24.21 (rs4295627, CCDC26), 9p21.3 (rs4977756, CDKN2A-CDKN2B), 11q23.3 (rs498872, PHLDB1), and 20q13.33 (rs6010620, RTEL1) as determinants of glioma risk. The authors investigated whether there is interaction between the effects of allergy and these 5 variants on glioma risk. Data from 5 case-control studies carried out in Denmark, Finland, Sweden, and the United Kingdom (2000-2004) were used, totaling 1,029 cases and 1,668 controls. Risk was inversely associated with asthma, hay fever, eczema, and "any allergy," significantly for each factor except asthma, and was significantly positively associated with number of risk alleles for each of the 5 single nucleotide polymorphisms. There was interaction between asthma and rs498872 (greater protective effect of asthma with increasing number of risk alleles; per-allele interaction odds ratio (OR) = 0.65, P = 0.041), between "any allergy" and rs4977756 (smaller protective effect; interaction OR = 1.27, P = 0.047), and between "any allergy" and rs6010620 (greater protective effect; interaction OR = 0.70, P = 0.017). Case-only analyses provided further support for atopy interactions for rs4977756 and rs498872. This study provides evidence for possible gene-environment interactions in glioma development.

MNS16A minisatellite genotypes in relation to risk of glioma and meningioma and to glioblastoma outcome

The human telomerase reverse transcriptase (hTERT) gene is upregulated in a majority of malignant tumours. A variable tandem repeat, MNS16A, has been reported to be of functional significance for hTERT expression. Published data on the clinical relevance of MNS16A variants in brain tumours have been contradictory. The present population-based study in the Nordic countries and the United Kingdom evaluated brain-tumour risk and survival in relation to MNS16A minisatellite variants in 648 glioma cases, 473 meningioma cases and 1,359 age, sex and geographically matched controls. By PCR-based genotyping all study subjects with fragments of 240 or 271 bp were judged as having short (S) alleles and subjects with 299 or 331 bp fragments as having long (L) alleles. Relative risk of glioma or meningioma was estimated with logistic regression adjusting for age, sex and country. Overall survival was analysed using Kaplan-Meier estimates and equality of survival distributions using the log-rank test and Cox proportional hazard ratios. The MNS16A genotype was not associated with risk of occurrence of glioma, glioblastoma (GBM) or meningioma. For GBM there were median survivals of 15.3, 11.0 and 10.7 months for the LL, LS and SS genotypes, respectively; the hazard ratio for having the LS genotype compared with the LL was significantly increased HR 2.44 (1.56-3.82) and having the SS genotype versus the LL was nonsignificantly increased HR 1.46 (0.81-2.61). When comparing the LL versus having one of the potentially functional variants LS and SS, the HR was 2.10 (1.41-3.1). However, functionality was not supported as there was no trend towards increasing HR with number of S alleles. Collected data from our and previous studies regarding both risk and survival for the MNS16A genotypes are contradictory and warrant further investigations.

XRCC1 and XRCC3 variants and risk of glioma and meningioma

Several single nucleotide polymorphisms (SNPs) affecting DNA repair capacity and modifying cancer susceptibility have been described. We evaluated the association of SNPs Arg194Trp, Arg280His, and Arg399Gln in the X-ray cross-complementing group 1 (XRCC1) and Thr241Met in the X-ray cross-complementing group 3 (XRCC3) DNA repair genes with the risk of brain tumors. The Caucasian study population consisted of 701 glioma (including 320 glioblastoma) cases, 524 meningioma cases, and 1,560 controls in a prospective population-based case-control study conducted in Denmark, Finland, Sweden, and the UK. The studied SNPs were not significantly associated with the risk of brain tumors. The highest odds ratios (ORs) for the associations were observed between the homozygous variant genotype XRCC1 Gln399Gln and the risk of glioma (OR = 1.32; 95% confidence interval, CI, 0.97-1.81), glioblastoma (OR = 1.48; 95% CI, 0.98-2.24), and meningioma (OR = 1.34; 95% CI, 0.96-1.86). However, in pair-wise comparisons a few SNP combinations were associated with the risk of brain tumors: Among others, carriers of both homozygous variant genotypes, i.e., XRCC1 Gln399Gln and XRCC3 Met241Met, were associated with a three-fold increased risk of glioma (OR = 3.18; 95% CI, 1.26-8.04) and meningioma (OR = 2.99; 95% CI, 1.16-7.72). In conclusion, no significant association with brain tumors was found for any of the polymorphisms, when examined one by one. Our results indicated possible associations between combinations of XRCC1 and XRCC3 SNPs and the risk of brain tumors.

Functional polymorphisms in folate metabolism genes influence the risk of meningioma and glioma

Folate metabolism plays an important role in carcinogenesis. To test the hypothesis that polymorphic variation in the folate metabolism genes 5,10-methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) influences the risk of primary brain tumors, we genotyped 1,005 glioma cases, 631 meningioma cases, and 1,101 controls for the MTHFR C677A and A1298C, MTRR A66G, and MTR A2756G variants. MTHFR C677T-A1298C diplotypes were associated with risk of meningioma (P = 0.002) and glioma (P = 0.02); risks were increased with genotypes associated with reduced MTHFR activity. The highest risk of meningioma was associated with heterozygosity for both MTHFR variants [odds ratio (OR), 2.11; 95% confidence interval (95% CI), 1.42-3.12]. The corresponding OR for glioma was 1.23 (95% CI, 0.91-1.66). A significant association between risk of meningioma and homozygosity for MTRR 66G was also observed (OR, 1.41; 95% CI, 1.02-1.94). Our findings provide support for the role of folate metabolism in the development of primary brain tumors. In particular, genotypes associated with increased 5,10-methylenetetrahydrofolate levels are associated with elevated risk.

The common D302H variant of CASP8 is associated with risk of glioma

Caspase 8 (CASP8) is a key regulator of apoptosis or programmed cell death, and, hence, a defense against cancer. We tested the hypothesis that the CASP8 polymorphism D302H influences risk of glioma through analysis of five series of glioma case patients and controls (n = 1,005 and 1,011, respectively). Carrier status for the rare allele of D302H was associated with a 1.37-fold increased risk (95% confidence interval, 1.10-1.70; P = 0.004). The association of CASP8 D302H with glioma risk indicates the importance of inherited variation in the apoptosis pathway in susceptibility to this form of primary brain tumor.

Comprehensive analysis of DNA repair gene variants and risk of meningioma

BACKGROUND

Meningiomas account for up to 37% of all primary brain tumors. Genetic susceptibility to meningioma is well established, with the risk among relatives of meningioma patients being approximately threefold higher than that in the general population. A relationship between risk of meningioma and exposure to ionizing radiation is also well known and led us to examine whether variants in DNA repair genes contribute to disease susceptibility.

METHODS

We analyzed 1127 tagging single-nucleotide polymorphisms (SNPs) that were selected to capture most of the common variation in 136 DNA repair genes in five case-control series (631 case patients and 637 control subjects) from four countries in Europe. We also analyzed 388 putative functional SNPs in these genes for their association with meningioma. All statistical tests were two-sided.

RESULTS

The SNP rs4968451, which maps to intron 4 of the gene that encodes breast cancer susceptibility gene 1-interacting protein 1, was consistently associated with an increased risk of developing meningioma. Across the five studies, the association was highly statistically significant (trend odds ratio = 1.57, 95% confidence interval = 1.28 to 1.93; P(trend) = 8.95 x 10(-6); P = .009 after adjusting for multiple testing).

CONCLUSIONS

We have identified a novel association between rs4968451 and meningioma risk. Because approximately 28% of the European population are carriers of at-risk genotypes for rs4968451, the variant is likely to make a substantial contribution to the development of meningioma.

Comprehensive analysis of the role of DNA repair gene polymorphisms on risk of glioma

Much of the variation in inherited risk of glioma is likely to be explained by combinations of common low risk variants. The established relationship between glioma risk and exposure to ionizing radiation led us to examine whether variants in the DNA repair genes contribute to disease susceptibility. We evaluated 1127 haplotype-tagging single-nucleotide polymorphisms (SNPs) supplemented with 388 putative functional SNPs to capture most of the common variation in 136 DNA repair genes, in five unique case-control series from four different countries (1013 cases, 1016 controls). We identified 16 SNPs associated with glioma risk at the 1% significance level. The highest association observed across the five independent case-control datasets involved rs243356, which maps to intron 3 of CHAF1A (trend odds ratio, 1.32; 95% confidence interval 1.14-1.54; P = 0.0002; false-positive report probability = 0.055, based on a prior probability of 0.01). Our results provide additional support for the hypothesis that low penetrance variants contribute to the risk of developing glioma and suggest that a genetic variant located in or around the CHAF1A gene contributes to disease risk.

Statins, Neuromuscular Degenerative Disease and an Amyotrophic Lateral Sclerosis-Like Syndrome

BACKGROUND

The WHO Foundation Collaborating Centre for International Drug Monitoring (Uppsala Monitoring Centre [UMC]) has received many individual case safety reports (ICSRs) associating HMG-CoA reductase inhibitor drug (statin) use with the occurrence of muscle damage, including rhabdomyolysis, and also peripheral neuropathy. A new signal has now appeared of disproportionally high reporting of upper motor neurone lesions.

AIM AND SCOPE

The aim of this paper is to present the upper motor neurone lesion cases, with other evidence, as a signal of a relationship between statins and an amyotrophic lateral sclerosis (ALS)-like syndrome. The paper also presents some arguments for considering that a spectrum of severe neuromuscular damage may be associated with statin use, albeit rarely. The paper does not do more than raise the signal for further work and analysis of what must be regarded as a potentially very serious and perhaps avoidable or reversible adverse reaction, though it also suggests action to be taken if an ALS-like syndrome should occur in a patient using statins.

METHODS

The 43 reports accounting for the disproportional reports in Vigibase (the database of the WHO Programme for International Drug Monitoring) are summarised and analysed for the diagnosis of an ALS-like syndrome. The issues of data quality and potential reporting bias are considered.

RESULTS

'Upper motor neurone lesion' is a rare adverse event reported in relationship to drugs in Vigibase (a database containing nearly 4 million ICSRs). Of the total of 172 ICSRs on this reported term, 43 were related to statins, of which 40 were considered further: all but one case was reported as ALS. In 34/40 reports a statin was the sole reported suspected drug. The diagnostic criteria were variable, and seven of the statin cases also had features of peripheral neuropathy. Of a total of 5534 ICSRs of peripheral neuropathy related to any drug in Vigibase, 547 were on statins. The disproportional reporting of statins and upper motor neurone lesion persisted after age stratification, and such disproportionality was not seen for statins and Parkinson's disease, Alzheimer's disease, extrapyramidal disorders, or multiple sclerosis-like syndromes.

DISCUSSION

Because the cases were sometimes atypical we propose the use of the term 'ALS-like syndrome' and speculate whether this is part of a spectrum of rare neuromuscular damage. The diagnosis of ALS is often problematic, and the insidiousness and chronicity of the disease make causality with a drug difficult to assess. The disproportionally high reporting makes this an important signal nevertheless, since ALS is serious clinically and statins are so widely used. Wide use of the statins also makes a chance finding more probable, but is unlikely to cause disproportional reporting when there are no obvious biases identified.

CONCLUSION

We emphasise the rarity of this possible association, and also the need for further study to establish whether a causal relationship exists. We do advocate that trial discontinuation of a statin should be considered in patients with serious neuromuscular disease such as the ALS-like syndrome, given the poor prognosis and a possibility that progression of the disease may be halted or even reversed.

Genetic variation in p53 and ATM haplotypes and risk of glioma and meningioma

BACKGROUND

P53 and ATM are central checkpoint genes involved in the repair of DNA damage after ionising irradiation, which has been associated with risk of brain tumours. Therefore, we tested the hypothesis that polymorphisms and haplotypes in p53 and ATM could be associated with glioma and meningioma risk.

MATERIAL AND METHODS

Six hundred and eighty glioma cases (298 glioblastoma (GBM)), 503 meningioma cases, and 1555 controls recruited in the Nordic-UK Interphone study, were analysed in association with three polymorphisms in p53 (rs2287499, rs1042533, rs1625895) and five polymorphisms in ATM ( rs228599, rs3092992, rs664143, rs170548, rs3092993). Haplotypes were constructed using the HAPLOSTAT program.

RESULTS

The global statistical test of glioblastoma and p53 haplotypes was p = 0.02. The haplotype analysis on glioblastoma revealed the 1-2-2 haplotype (promotor-codon72-intron 6) had a frequency of 6.1% in cases compared with 9.8% in controls (p = 0.003). The 1-2-1 haplotype was significantly more frequent in GBM cases, 10.2%, than in controls, 7.3% (p = 0.02). The haplotype analysis in ATM revealed an increased frequency of the 1-1-1-2-1 haplotype in meningioma cases (33.8%) compared with controls (30.3%) (p = 0.03). The 2-1-2-1-1 haplotype had a lower frequency in meningioma cases (36.1%) than controls (40.7%) (p = 0.009).

CONCLUSIONS

This study found both positive and negative associations of haplotypes in p53 for glioblastoma and ATM for meningioma. This study provides new data that could add to our understanding of brain tumour susceptibility.

Influence of DNA repair gene polymorphisms on the yield of chromosomal aberrations

We evaluated the influence of several DNA repair gene polymorphisms on the frequency of chromosomal aberrations (CAs) analyzed in peripheral lymphocytes, using the fluorescence in situ hybridization technique. The CA data were obtained from an earlier study of 84 healthy nonsmokers (48 women and 36 men) carefully characterized for indoor radon exposure. The frequency of translocations showed a wide interindividual variability, which was only partly explained by age. To investigate the potential role of DNA repair polymorphisms in this variation, genotypes of DNA repair genes OGG1 (codon 326), XPD (codon 751), XRCC1 (X-ray repair cross-complementing group 1) (codons 194, 280, and 399), and XRCC3 (X-ray repair cross-complementing group 3) (codon 241) were determined from leukocyte DNA using polymerase chain reaction-based methods. Negative binomial regression models were applied to evaluate the effect of the polymorphisms and other factors (age, gender, radon exposure, and medical exposure) on the frequency of CAs. No interactions between genotypes and radon, medical exposure, or gender were found. Carriers of the XRCC1 codon 280His variant allele had a two-fold increase (frequency ratio [FR] = 2.01, 95% confidence interval [CI] = 1.01-3.98; P = 0.046) in unstable exchanges (dicentrics and ring chromosomes). In addition, the XRCC3 codon 241 homozygous variant genotype (Met/Met) was associated with an increase (FR = 1.70, 95% CI = 1.06-2.74; P = 0.028) in two-way translocations when age was taken into account in the analysis. Our data suggest that the XRCC1 280His and XRCC3 241Met alleles affect individual CA levels, most probably via influencing the DNA repair phenotype.

Selective serotonin reuptake inhibitors in pregnant women and neonatal withdrawal syndrome: a database analysis

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) have been associated with withdrawal symptoms. We investigated whether use of these drugs in pregnant women might cause neonatal withdrawal syndrome.

METHODS

An association between paroxetine and neonatal convulsions was identified in December, 2001, by the data mining method routinely used to screen the WHO database of adverse drug reactions. An information component (IC) measure was used to screen for unexpected adverse reactions relative to the information in the database. We then assessed cases of neonatal convulsions and neonatal withdrawal syndrome associated with drugs included in the anatomical therapeutic chemical groups N06AB and N06AX.

FINDINGS

By November, 2003, a total of 93 suspected cases of SSRI-induced neonatal withdrawal syndrome had been reported, and were regarded as enough information to confirm a possible causal relation. 64 of the cases were associated with paroxetine, 14 with fluoxetine, nine with sertraline, and seven with citalopram. The IC-2 SD for the group became greater than 0 in the first quarter of 1991, and the IC increased to 2.68 (IC-2 SD 0.32) by the second quarter of 2003. For each individual compound, the IC-2 SD was greater than 0.

INTERPRETATION

SSRIs, especially paroxetine, should be cautiously managed in the treatment of pregnant women with a psychiatric disorder.

Assessing the impact of drug safety signals from the WHO database presented in 'SIGNAL': results from a questionnaire of National pharmacovigilance Centres

INTRODUCTION

A major task for the Uppsala Monitoring Centre (UMC) is to detect early signals of suspected adverse drug reactions (ADRs) in the WHO Database. The database currently contains over 2.8 million spontaneously reported ADR case reports continuously collected by National Pharmacovigilance Centres in countries participating in the WHO Programme for International Drug Monitoring. The database is scanned every quarter and drug-ADR combinations are filtered out using different selection criteria intended to catch potential international drug safety signals at an early stage. Summary case data are reviewed by experts on the UMC's review panel and the signals are presented to the Programme members in the restricted circulation document entitled 'SIGNAL'.

OBJECTIVE

The aim of the study was to investigate: (i). how the signals presented in 'SIGNAL' are used; (ii). if they reach the right target group; (iii). if they are of interest and relevance to the recipients; (iv). if they are timely and; (v). if they make any difference. We were also interested in knowing the view of member countries regarding the definition of what a signal is.

METHODS

A questionnaire was sent out to 71 countries participating in the WHO Programme. The recipients were asked to state what actions were taken for 26 different signal headings included in three issues of 'SIGNAL' sent out during 2001 and to rate how useful they considered these topics to be.

RESULTS

Responses were received from 45 countries (63%). The Centres' average ratings of relevance, importance and usefulness on a scale 1-10 of the selected 26 signals were all above the expected average rating 5.5. The content of 'SIGNAL' in general was seen as always or often useful in 63.5% of the respondents. In 2001, 17 countries took actions on at least one signal. Actions were rarely taken without considering the signal from the UMC. All responding centres agreed on the WHO definition of a signal, but there were differences in the interpretation of what constitutes a signal.

CONCLUSION

The 'SIGNAL' publication is timely, plays an important role and has a direct impact on drug safety issues handled by members of the WHO Programme for International Drug Monitoring.

Hereditary minisatellite mutations among the offspring of Estonian Chernobyl cleanup workers

A single accidental event such as the fallout released from the Chernobyl reactor in 1986 can expose millions of people to non-natural environmental radiation. Ionizing radiation increases the frequency of germline mutations in experimental studies, but the genetic effects of radiation in humans remain largely undefined. To evaluate the hereditary effects of low radiation doses, we compared the minisatellite mutation rates of 155 children born to Estonian Chernobyl cleanup workers after the accident with those of their siblings born prior to it. All together, 94 de novo paternal minisatellite mutations were found at eight tested loci (52 and 42 mutants among children born after and before the accident, respectively). The minisatellite mutation rate was nonsignificantly increased among children born after the accident (0.042 compared to 0.036, OR 1.33, 95% CI 0.80-2.20). Furthermore, there was some indication of an increased mutation rate among offspring born after the accident to workers who had received doses of 20 cSv or above compared with their siblings born before the accident (OR 3.0, 95% CI 0.97-9.30). The mutation rate was not associated with the father's age (OR 1.04, 95% CI 0.94-1.15) or the sex of the child (OR 0.95, 95% CI 0.50-1.79). Our results are consistent with both no effect of radiation on minisatellite mutations and a slight increase at dose levels exceeding 20 cSv.

Microdialysis measurements demonstrate a shift to nonoxidative glucose metabolism in rat pancreatic islets transplanted beneath the renal capsule

BACKGROUND

We aimed to use microdialysis to assess, for the first time, the internal milieu of pancreatic islet grafts.

METHODS

One month after transplantation, microdialysis probes were inserted into syngeneic rat islet transplants (500-700 islets) placed beneath the renal capsule of nondiabetic or diabetic recipients. The number of grafted islets was purposely chosen not to cure the diabetic recipients.

RESULTS

During an intravenous glucose challenge, insulin concentrations increased in parallel in serum and in the graft interstitium of nondiabetic animals suggesting the existence of a functionally well-established vascularization. Diabetic recipients had both a lower serum and dialysate insulin concentration than normoglycemic animals. The lactate/pyruvate ratios were determined in the dialysates as a measure of the degree of anaerobic metabolism in the islet grafts. Lactate/pyruvate ratios were between 50 and 100 in grafts of both nondiabetic and diabetic recipients, and they almost doubled in response to the intravenous glucose challenge in the grafts of nondiabetic recipients. In comparison, lactate/pyruvate ratios were approximately 12 in the medium of cultured islets incubated at low glucose (5.6 mmol/L) or high glucose (16.7 mmol/L) concentrations.

CONCLUSIONS

The microdialysis technique has proven to be a valuable tool for evaluating the internal environment of islet transplants. Moreover, the high lactate/pyruvate ratio suggests that islet grafts have an increased anaerobic glucose metabolism.

Effectiveness of radiological image data compression

This study was designed to evaluate effectiveness of radiological image data compression in terms of image quality and archiving material costs using DLT tapes, and to assess the relationship between loss of quality and cost savings. Six radiologists used Subjective Fidelity Criteria (SFC) in random fashion to evaluate the quality of 105 digitally acquired radiological images. In addition, 5 radiologists and 2 nonradiologists evaluated at random three phantom images exposed in conditions mimicking chest, bone, and colon examinations, displayed in five modes (a total of 15 images). Both patient images and phantom images were submitted to 3:1 (Ziv-Lempel method) and 10:1 compression (wavelet-based compression method). Cost information on material cost savings and the effect of compression on tape space requirements were compared. The results indicate that image quality was not degraded using either of the compression ratios. The interobserver proportion of agreement exceeded overwhelmingly the limit of a good proportion of agreement regarding each compression ratio and each image type. The divergence in the rest of the assessments was not consistent. The adoption of 10:1 compression would not bring a substantial decrease of archiving costs as compared to the total yearly operating costs, and especially as considering the consequences of possible image quality deterioration.

Substance P endopeptidase-like activity is altered in various regions of the rat central nervous system during morphine tolerance and withdrawal

In this study the level of a substance P endopeptidase (SPE)-like activity was measured in different regions of the rat central nervous system (CNS) after chronic administration of morphine. Male rats (200-220 g) were randomly divided into four groups. Two groups were injected (s.c.) with morphine (10 mg/kg) twice daily, whereas the other two received saline under identical conditions. After 8 days, when animals were completely tolerant to morphine, one of the morphine-treated groups and one group of saline-injected rats were given naloxone (s.c. 2 mg/kg). Withdrawal signs were observed and recorded. The enzyme activity was measured in extracts of the various CNS tissues by following the conversion of synthetic substance P (SP) to its N-terminal fragment SP(1-7) using a radioimmunoassay detecting this product. In discrete CNS areas including periaqueductal grey, spinal cord, substantia nigra and ventral tegmental area (VTA) a significant increase in enzyme activity was observed in the withdrawal group, while tolerant rats exhibited decreased SPE-like activity in the striatum (see Table 1). The enhanced enzyme activity during withdrawal is in agreement with our previous observation that the levels of SP(1-7) in rat brain are affected following naloxone precipitated withdrawal. In some tissues, including VTA, a correlation between the SPE-like activity and the intensity of the opioid abstinence was observed. Our result suggests that the elevated SPE-like activity is responsible for enhanced release of SP(1-7) in rats during morphine withdrawal, affirming a modulatory or regulative role of this enzyme in this state of opioid dependence.

Comparison between direct ion storage and thermoluminescence dosimetry individual monitoring systems, and Internet reporting

A new electronic direct ion storage (DIS) dosemeter allows accumulated personal dose equivalent Hp(d) at depths of 10 mm and 0.07 mm to be monitored in a few seconds by inserting the dosemeter into a local reader without deleting the accumulated dose. The DIS system meets general requirements on individual monitoring of hospital personnel using ionising radiation. It differs greatly from off-line thermoluminescence dosimetry systems and offers many additional benefits. The non-volatile reading takes only 5 s, is taken as often as needed, and the data are collected into a dose database, where background radiation is subtracted. Individual personnel doses are reported in Intranet as well as on the Internet at regular intervals to the National Regulatory Authorities.

N-Hydroxyguanidine compound 1-(3,4-dimethoxy- 2-chlorobenzylideneamino)-3-hydroxyguanidine inhibits the xanthine oxidase mediated generation of superoxide radical

We here show that the novel N-hydroxyguanidine derivative PR5 (1-(3, 4-dimethoxy-2-chlorobenzylideneamino)-3-hydroxyguanidine) is acting as an alternative electron acceptor in xanthine oxidase catalyzed oxidation of xanthine. The reduction product is the corresponding guanidine derivative 1-(3, 4-dimethoxy-2-chlorobenzylideneamino)guanidine (PR9). The reaction occurs under both anaerobic and aerobic conditions. Moreover, EPR measurements show that the action of PR5 is associated with the inhibition of superoxide radical formation seen under aerobic conditions. PR5 also supports xanthine oxidase catalyzed anaerobic oxidation of NADH. Kinetic studies indicate that increasing xanthine concentration significantly increases the apparent K(m) of PR5, but it remains unaltered by changing NADH concentration. Moreover, the molybdenum center inhibitor allopurinol inhibits the PR5-sustained oxidation of xanthine and NADH equally well, whereas the flavin adenine dinucleotide site inhibitor diphenyliodonium (DPI) markedly inhibits only the PR5-sustained oxidation of NADH. We suggest that PR5 binds and becomes reduced at the molybdenum center of the xanthine oxidase. We also found that both PR5 and its reduction product PR9 can inhibit the oxygen-sustained xanthine oxidase reaction. The properties of PR5 suggest that it is a member of a novel class of compounds which we have termed xanthine oxidase electron acceptor-inhibitor drugs. The potential use of xanthine oxidase electron acceptor-inhibitors in the prevention of free radical mediated tissue damage in organ ischemia-reperfusion diseases is discussed.

Localization of radiation-induced chromosomal breakpoints along human chromosome 1 using a combination of G-banding and FISH

PURPOSE

To determine the exact location of radiation-induced chromosomal breakpoints along the euchromatic or heterochromatic regions: G-light and G-dark bands, respectively.

MATERIALS AND METHODS

The distribution of radiation-induced chromosomal breakpoints was scored in human lymphocytes irradiated in vitro with 3 Gy of gamma-radiation. Image analysis was applied to combine G-banded and FISH-painted images of the human chromosome 1.

RESULTS

A total of 195 chromosomal breakpoints in 176 cells with structural chromosomal aberrations was used for the present analysis. Radiation-induced breakpoints were found to be distributed randomly with respect to the p or q arms of chromosome 1 and specific band or band length, but more breakpoints were mapped to G-light than to G-dark bands, the difference being statistically significant.

CONCLUSIONS

The results can well be interpreted in terms of concepts of existing models of nuclear architecture, chromatin structure and transcriptional activities of the chromatin, which can influence the induction of primary chromosomal aberrations by gamma-rays. Differential repair of randomly produced primary aberrations may also explain the non-random distribution of radiation-induced breakpoints.

Effects of the androgenic anabolic steroid, nandrolone decanoate, on adrenocorticotropin hormone, corticosterone and proopiomelanocortin, corticotropin releasing factor (CRF) and CRF receptor1 mRNA levels in the hypothalamus, pituitary and amygdala of the rat

There is increasing abuse of androgenic anabolic steroids (AAS) by non-athletes. AAS abuse has been associated with psychiatric symptoms such as mania, major depression and aggression and the development of dependence. Little is known about the effects of AAS on hypothalamic-pituitary-adrenal axis function or corticotropin releasing factor, which may be involved in mediating some of the psychiatric symptoms associated with AAS abuse. Male Sprague-Dawley rats received one daily intra-muscular injection of the AAS nandrolone decanoate (ND, 15 mg/kg) or vehicle for 3 days. Animals were sacrificed either 1 h or 24 h after the last injection, brain regions dissected and trunk blood collected. Corticotropin releasing factor (CRF), CRF receptor1 (CRF-R1) and proopiomelanocortin (POMC) mRNAs were measured with solution hybridization/RNase protection. Circulating levels of corticosterone and adrenocorticotropin hormone (ACTH) were determined using radioimmunoassays. One hour following the last injection, ND significantly increased circulating levels of both corticosterone and ACTH levels. In the amygdala, CRF mRNA levels were unchanged 1 h after the last injection of ND but were significantly reduced at 24 h. The same was found for hypothalamic POMC. No significant AAS effects were observed on: hypothalamic CRF mRNA; POMC mRNA in the amygdala or CRF R1 mRNA in the anterior pituitary.

p53 and K-ras gene mutations in carcinoma of the rectum among Finnish women

AIMS/BACKGROUND

The aim of this study was to identify p53 and K-ras gene mutations in carcinoma of the rectum among Finnish women. Mutation patterns might give clues to aetiological factors when comparisons are made with other human tumours.

METHODS

Of 134 women with carcinoma of the rectum, paraffin wax embedded specimens of the tumour tissue were obtained from 118 patients. Genomic DNA was extracted, and exons 4-8 of the p53 gene and codons 12/13 and 61 of the K-ras gene were amplified, and analysed for mutations by single strand conformation polymorphism and direct sequencing. The production of p53 and K-ras proteins was studied by immunohistochemistry.

RESULTS

The overall crude frequency for mutations in the p53 gene was 35% but the true frequency appears to be higher (up to 56%). In the K-ras gene, the mutation frequency (15%) was significantly lower than that reported for colon cancer. In the p53 gene, the mutation frequency increased significantly with patient age. In a high proportion of patients (14%) the rectal tumours contained small subclones of tumour cells that displayed extremely rare mutations at codons 110 and 232 of the p53 gene. Hot spot codon 175 mutations were significantly less common in rectal cancer than in cancer of the colon.

CONCLUSIONS

Rectal cancer among Finnish women has characteristics in the mutations of the p53 and K-ras genes that are uncommon in other human tumours, including cancer of the colon. A biological explanation of these findings is not clear at present, but might be associated with an unidentified genetic factor in Finland.

K-ras and p53 mutations and overexpressions as prognostic factors in female rectal carcinoma

BACKGROUND

The present study was undertaken to determine the prognostic significance of K-ras, p53 and bcl-2 in female rectal carcinoma.

MATERIALS AND METHODS

The mutations in K-ras and p53 genes were analysed using SSCP and direct sequencing. The expression of K-ras, bcl-2 and p53 proteins was determined immunohistochemically.

RESULTS

Mutations of K-ras and p53 genes were detected in 12% and 38% of the tumours, respectively. The prevalence of K-ras overexpression was 67%. K-ras mutations were not associated with survival. However, more favourable survival was observed for patients with K-ras overexpression than with normal expression (adjusted hazard ratio from Cox model 0.4, 95% CI 0.2-0.8). Mutation or overexpression of p53 were not associated with survival.

CONCLUSIONS

It may be possible, that the mutations and protein overexpression of K-ras and p53 in female rectal carcinoma have different clinical impact on patient survival as suggested in previous studies concerning colorectal carcinoma of both sexes.

Sublethal damage repair capacity in carcinoma cell lines with p53 mutations

BACKGROUND

The previous findings that sublethal damage repair (SLDR) capacity varies between carcinoma cell lines and that the inherent radiosensitivity of these lines tends to be higher in connection with p53 mutations lead us to study the possible role of p53 gene in the regulation of SLDR. The activation of p53 gene by irradiation is known to cause changes in cell cycle progression. Thus, p53 status probably has effects on cellular radiosensitivity, theoretically through modulating repair processes.

METHODS

The SDLR capacity of 17 head and neck carcinoma cell lines was determined in split-dose experiments using a 96-well plate clonogenic assay. The SLDR capacity as well as the inherent radiosensitivity were compared with the p53 status of the cells.

RESULTS

The SLDR capacity varied markedly also between cell lines of similar radiosensitivity, but there was a tendency of the more sensitive cells to be more SLDR proficient .(r = -.69; p = .0016). The (beta-values obtained from linear quadratic equation correlated well with the observed amount of SLDR (r = .73; p = .0006). With one exception, those cell lines having p53 mutations showed higher SLDR than those with no mutations (p = .0017). In many of these cell lines, the mutations caused either total loss of the p53 protein or major, probably functional changes in it. The cell line UT-SCC-16A, showing no SLDR in the experiments, had two mutation points in different alleles, perhaps having less effect on the protein function.

CONCLUSION

This extended material confirmed the previous result that the SLDR capacity tends to increase with increasing radiosensitivity in carcinoma cell lines. A clear correlation between p53 mutations and SLDR capacity was found. The SLDR depended, however, on loss of normal p53 function, which implies that the p53-mediated G1 arrest is not as important in this repair process, as would have been expected.

The bcl-2 gene status of human head and neck cancer cell lines

The bcl-2 oncogene was originally found in the translocation in a pre-B cell acute lymphocytic leukemia cell line. Since then a high expression of Bcl-2 has been found in many types of cancer. The bcl-2 gene encodes an intracellular membrane-associated protein. Overexpression of bcl-2 inhibits apoptosis induced by many drugs and radiation. In this study the bcl-2 gene status of 9 human head and neck squamous cell carcinoma cell lines was studied. Mutations of the bcl-2 gene were studied at mRNA and DNA levels. The presence and abundance of the Bcl-2 protein in cells were also investigated. In earlier studies the p53 tumour suppressor gene was screened for point mutations, and the radiosensitivity of these cell lines was measured. We were able to amplify bcl-2 cDNA from 5 of the 9 cell lines, which shows that bcl-2 was expressed in these cells. No point mutations were found in the bcl-2 gene in any of these cell lines. Loss of heterozygosity was observed in 2 cell lines at the bcl-2 locus, and these cell lines had no detectable levels of bcl-2 mRNA or Bcl-2 protein. The Bcl-2 protein was abundant in the cell lines with the wild-type p53 gene, and these cell lines were radioresistant. The Bcl-2 protein was also found in many other cell lines in mitotic cells. It seems that cells expressing bcl-2 are radioresistant, and even functional p53 cannot induce apoptosis in these cells.

p53 mutations in human head and neck cancer cell lines

The p53 tumour suppressor gene is commonly mutated in human cancers. We performed a molecular analysis of the frequency and spectrum of p53 gene mutations in 40 cell lines (23 from oral cavity tumours and 17 from larynx tumours) derived from 33 patients with squamous cell carcinoma of the head and neck (SCCHN). Using PCR, SSCP, and sequence analysis, we detected the mutated p53 gene in 26 patients (79%); in 23 patients (70%) the wild-type allele of the p53 gene was deleted. Four patients had 2 p53 gene mutations each, and thus the total number of p53 mutations observed was 30. Seven patients had 2 cell lines each, established from the primary and recurrent/metastatic tumour, and the status of the p53 gene (mutant or normal) was identical in both cell lines. Forty percent of the mutations were transitions, 33% transversions, and 27% deletions, insertions and other more complicated changes. In oral cavity tumours the predominant mutation type was G:C-->A:T transition at a CpG site (50% of mutations), and in larynx tumours the predominant type was G:C-->T:A transversion (50% of mutations). These suggest endogenous and exogenous factors in tumour etiology. The G:C-->T:A transversions in larynx tumours are probably associated with mutagenic components in the cigarette smoke, but the causative factor in G:C-->A:T transitions (apparent oxidative damage) remains to be identified.

p53 mutations associated with increased sensitivity to ionizing radiation in human head and neck cancer cell lines

The p53 tumour suppressor gene is activated following cellular exposure to DNA-damaging agents. The functions of wild-type p53 protein include transient blocking of cell cycle progression, direct or indirect stimulation of DNA repair machinery and triggering of apoptosis if DNA repair fails. Therefore, the status of p53 protein may be critically associated with tumour cell radiosensitivity. In the present study we examine the intrinsic radiosensitivity of 20 human carcinoma cell lines derived from 15 patients with different types of head and neck tumour. Radiosensitivities were measured in a 96-well plate clonogenic assay in terms of the mean inactivation dose, surviving fraction at 2 Gy, and constants alpha and beta in the linear quadratic survival curve. The p53 allele status was determined by amplifying exons 4-10 by the polymerase chain reaction (PCR), screening for mutations using single-strand conformation polymorphism (SSCP) analysis and determining the exact type and location of a mutation by direct sequencing. The results showed that prevalence of p53 mutations in squamous cell carcinoma (SCC) cell lines is high (80%), and that deletion of one or both wild-type alleles is common (75%). Intrinsic radiosensitivity of the cell lines varied greatly in terms of mean inactivation dose, from 1.4 +/- 0.1 to 2.6 +/- 0.2 Gy. Radiosensitivity correlated well with the p53 allele status so that cell lines carrying a wild-type p53 allele were significantly (P < 0.01) more radioresistant (mean inactivation dose 2.23 +/- 0.15 Gy) than cell lines which lacked a wild-type gene (1.82 +/- 0.24 Gy). Evaluation of our own results and those published in the literature lead us to conclude that absence of the wild-type p53 allele in human head and neck cancer cell lines is associated with increased radiosensitivity. However, the sensitivity is also strongly dependent on the exact type and location of the p53 mutation.

Increased radiosensitivity is associated with p53 mutations in cell lines derived from oral cavity carcinoma

The curability of oral cavity carcinomas, as well as of other head and neck cancers, varies remarkably especially in more advanced disease. Radiotherapy and surgery, including large operations, are currently combined, but as new radiotherapy regimens are being introduced, the need for predictive assays has increased in order to plan a suitable individual treatment for the patient. Variations in intrinsic radiation sensitivity of cancer cells cannot alone explain differences in therapy outcome, and thus additional predictive variables have to be searched. Mutations in the p53 tumor suppressor gene are found in most head and neck tumors, which has led us to study the possible association between these mutations and radiation sensitivity. We analyzed 16 cell lines from oral cavity carcinomas and found a remarkable variation in radiosensitivity (AUC 1.7-2.3 Gy and SF2 0.31-0.51). The p53 gene was mutated in 11/16 cell lines, and these cells were also significantly more sensitive than those with wildtype p53 (AUC 1.9 +/- 0.2 Gy and 2.3 +/- 0.2 Gy, respectively, p = 0.023). Structural alterations in the p53 gene were also observed in three of the relatively resistant cell lines, which indicates that not all mutations are critical in this respect.

Standardization of medical imaging in Europe: an integrated initiative

The successful implementation of PACS (or IMACS) depends on the integration of image and image related data handling systems in an overall hospital information system (HIS) and other departmental information systems (DIS), one of which is radiology information system (RIS). With respect to standardization in the medical imaging field, this integration cannot be looked at separately from the overall prospect of standardization in medical informatics. All relevant standardization work done outside health care should be taken into account. This paper gives an overview of the work within Technical Committee TC 251 'Medical Informatics', of the European Standardization Committee, CEN, with special focus on its Working Group 4 'Medical Imaging and Multimedia'. An indication of the overall framework and relations towards ongoing work is given, with emphasis on short-term targets. The standards to be proposed are collectively called MEDICOM, standing for medical image communication.

Diagnosis of Duchenne and Becker muscular dystrophies by polymerase chain reaction. A multicenter study

OBJECTIVE--To assess the efficiency, reliability, and ease of use of DNA diagnosis for Duchenne and Becker muscular dystrophies (DMD/BMD) using the polymerase chain reaction (PCR). DESIGN--DNA from the patients was screened for deletion mutations using multiplex PCR, and the results were compared with those obtained by Southern blot analysis. The PCR multiplex reaction detects nine specific "hot-spot" exons in the dystrophin gene while the Southern analysis detects 66 specific dystrophin gene restriction fragments. The multiplex reaction requires 50-fold less DNA than Southern analysis and thus is considerably more sensitive. SETTING--Fourteen university-affiliated and private genetic disease diagnostic laboratories. PATIENTS--Male patients with clinical signs of DMD/BMD. Cases were selected for analysis randomly, without knowledge of whether a deletion was present within the dystrophin gene. MAIN OUTCOME MEASURES--The percentage of cases that were detectable by multiplex PCR in comparison with Southern analysis, the frequency, extent, and location of the detected deletion mutations. In some cases, duplication mutations were monitored. RESULTS--The accuracy of a single PCR multiplex amplification (nine exons) was compared with Southern analysis with 10 cDNA probes that cover the full length of the gene. The multiplex PCR analytic method detected 82% of those deletions detected by Southern analysis methods. In one of 745 analyses, the multiplex method suggested a single exon deletion, which was not confirmed by Southern analysis, representing a false-positive rate of 0.013%. CONCLUSIONS--Multiplex PCR represents a sensitive and accurate method for deletion detection of 46% of all cases of DMD/BMD. The method requires 1 day for analysis, is easy to perform, and does not use radioactive tracers. As such, multiplex PCR represents an efficient and rapid method for prenatal or postnatal diagnosis of DMD/BMD.

Dynamic pulmonary imaging: performance properties of a digital fluoroscopy system

The physical characteristics of dynamic pulmonary imaging with digital fluoroscopy, which differ from those in DSA equipment, have been determined. The spectral distributions and mean energies were calculated and corresponding exposures with varying high voltage and copper filtration (60-100 kVp, 0-2.83 mm Cu) were measured. The utilization of 90-100 kVp with a filter consisting of 1.39 mm Cu and 3 mm Al minimized disturbing skeletal artifacts and reduced the radiation exposure by a factor of approximately 5 in comparison with imaging at 60 kVp without copper filtration. Simultaneously, the measured signal decreased by about 25%. The mean energy of this spectrum exceeded that of 140 kVp chest imaging. The dynamic pulmonary imaging method produces logarithmically transformed x-ray transmittance values linearly related (r = -0.999) to water thickness between 7-10.5 cm, which is equivalent to the normal range of the chest in pediatric patients. A good linear correlation (r = 0.933,N = 92) was obtained when the change in transmitted radiation was compared with tidal volume measured in a rabbit model using a pneumotachometer. The results indicate that the method is applicable for quantitative measurements of pulmonary ventilation. Changes in tidal ventilation can be measured with this noninvasive x-ray imaging technique.

Dynamic imaging of pulmonary ventilation. Description of a novel digital fluoroscopic system

A new fluoroscopic imaging device consisting of an AT-microcomputer and a digital image memory unit has been used in experimental and clinical ventilation studies during a 2-year period. Digital images with 256 shades of gray were collected during one to 3 ventilation cycles at the rate of 6 to 25 images/s and stored on an optical laser disc. Both subtracted time interval difference (TID-) images and images relative, for example, to the mean image of the cycle (REL-images) were produced. The series of images could also be evaluated dynamically using animation sequences or analyzed using region of interest calculations. The method gave dynamic information with adequate spatial resolution and was easy to use in clinical practice. The radiation dose was kept low due to the high kilovoltage and heavy beam filtration technique. In experimental studies the software enabled flexible measurements of physiological pulmonary parameters.

Dynamic imaging of pulmonary ventilation in children using digital subtraction radiography

Digital subtraction radiography is a sensitive method for imaging changes in pulmonary aeration during the respiratory cycle. The findings of 75 consecutive dynamic pulmonary examinations performed on 49 pediatric patients using this technique were reviewed together with the findings at chest radiography and, in 18 cases, with bronchoscopy. Symmetric diaphragmatic movement and synchronous, homogeneous variation in the attenuation of lung parenchyma indicated normal conditions in 9 (18%) patients. The most common abnormal finding (36 patients) was an asynchronous variation in the attenuation of the lung parenchyma. A greatly diminished or absent variation in attenuation was diagnostic for a serious air passage obstruction in 7 children. Other abnormal findings were a lowered amplitude of diaphragmatic movement, asynchronous diaphragmatic movement and mediastinal shift. In 10 patients (20%) the dynamic study showed parenchymal abnormalities when chest radiography was normal. Bronchoscopy was performed in 4 of these 10 patients and showed abnormalities in each case.

Acute bronchial obstruction: an experimental rabbit model study

An animal model of bronchial obstruction was developed to radiologically follow up the development of postobstructive pulmonary changes. The study material consisted of 21 healthy rabbits (New Zealand White) of which 5 animals served as controls. A piece of Surgicel (Ethicon) shaped as a 3 x 3 x 10 mm cylinder was placed endobronchially through a 3-mm bronchoscope. The animals were followed up radiologically and endoscopically during the first 30 min after which the bronchoscope was extracted. Sixteen animals were followed up for at least 4 h and, in 4 animals, the foreign body (FB) was removed after 24 h. During follow-up, total collapse of the lung was observed after 1-4 h in all but 2 animals with obstruction of the main brochus. After extraction of the FB, atelectasis of the respective lung had resolved within 24 h. The animal model developed in the present study seems to be rather physiological resembling the development of pulmonary atelectasis in pediatric patients.

The molecular basis for Duchenne versus Becker muscular dystrophy: correlation of severity with type of deletion

About 60% of both Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) is due to deletions of the dystrophin gene. For cases with a deletion mutation, the "reading frame" hypothesis predicts that BMD patients produce a semifunctional, internally deleted dystrophin protein, whereas DMD patients produce a severely truncated protein that would be unstable. To test the validity of this theory, we analyzed 258 independent deletions at the DMD/BMD locus. The correlation between phenotype and type of deletion mutation is in agreement with the "reading frame" theory in 92% of cases and is of diagnostic and prognostic significance. The distribution and frequency of deletions spanning the entire locus suggests that many "in-frame" deletions of the dystrophin gene are not detected because the individuals bearing them are either asymptomatic or exhibit non-DMD/non-BMD clinical features.

Gene deletions in X-linked muscular dystrophy

Of the approximately 170 families with X-linked muscular dystrophy of the Duchenne (DMD) and Becker (BMD) type in Finland, we have studied 90 unrelated patients for intragenic deletions by using the cDNA probes described by Koenig et al. Forty-five patients (50%) had molecular deletions of one or several of the 65 exon-containing HindIII fragments. In six deletion cases junction fragments of altered size were seen. Thirty-eight (84%) of the 45 deletions were detected using only two (1-2a and 8) of the six cDNA subclones. Using a wheelchair age of 12 years to distinguish between DMD and BMD, we found that the proportions of patients with deletions were similar. Deletions were equally common in familial and sporadic disease. BMD was more commonly caused by deletions in the 5' end of the gene than was DMD. In at least three instances deletions of similar type resulted in diseases of similar severity. Of 14 patients with mental retardation seven had deletions; six of these comprised exons contained in probe 8. We conclude that cDNA hybridization studies provide a powerful diagnostic tool in DMD and BMD and that they promise to produce better insights into molecular-clinical correlations.

Organ and tumor distribution of (18F)-2-fluoro-2-deoxy-D-glucose in fasting and non-fasting rats

Differences in the uptake of (18F)-2-fluoro-2-deoxy-D-glucose ((18F)FDG) in various normal organs and the Rous sarcoma of fasted and unfasted rats were studied at 5, 15, 30, 60, and 120 minutes after i.v. injection. The uptake of (18F)FDG in the tumor, spleen, and testis increased for 120 minutes, while uptake in the other organs was either level (brain, heart, white fat) or cleared off. The uptake was higher in the tumor than in the normal organs. The fraction of viable tumor tissue as measured morphometrically correlated intraindividually with the uptake of (18F)FDG--an increase of 1% of vital tumor corresponded to a 1.01-fold increase in tumor uptake of (18F)FDG. The nutritional state was of importance for the uptake of (18F)FDG into the heart, testis and brown fat. (18F)FDG is taken quantitatively up by the viable parts of the Rous tumor; this may make it possible to follow the response of treatment in individual tumors also in man with (18F)FDG and positron emission tomography (PET).