Prognostic value of codon 918 (ATG-->ACG) RET proto-oncogene mutations in sporadic medullary thyroid carcinoma

We have determined the frequency of 918 RET proto-oncogene mutations (ATG-->ACG) in primary MTC tumors and metastases and correlated the presence or absence of this mutation with the clinical outcome of patients suffering from sporadic medullary thyroid carcinoma (MTC). A total of 197 samples, consisting of both primary tumors and lymph node metastases from 34 patients with sporadic MTC, were collected for PCR analysis of the RET 918 mutation. In 75 of the samples (38%), codon 918 (ATG-->ACG) mutations could be detected. The mutations showed a heterogeneous distribution: 21/34 patients (62%) had mutations in at least 1 tumor sample, and in 13 patients (38%) the mutation was present in all examined samples. Patients were considered 918mt when at least 1 tumor sample showed the RET 918 mutation. These 918mt and 918 wild-type (918wt) patients did not differ significantly concerning sex, age at diagnosis, TNM stage at diagnosis, number of examined tumor samples or follow-up time. However, 918mt patients showed more aggressive development of distant metastases during follow-up (p = 0.032, Fisher's exact test) with decreased metastases-free survival (p < 0.005, log-rank test). Furthermore, 918mt patients had a significantly lower survival rate than 918wt patients (p = 0.048, log-rank test). These data show that the RET codon 918 mutation has a prognostic impact on patients with sporadic MTC which may influence follow-up treatment.

Antenatal betamethasone treatment reduces synaptophysin immunoreactivity in presynaptic terminals in the fetal sheep brain

Knowledge of morphofunctional effects on the fetal brain induced by exogenous glucocorticoids is limited. Recently, we reported alterations of both the neuronal cytoskeleton and electrocortical function in the ovine fetal brain after antenatal betamethasone treatment in doses used in perinatal medicine. In the present study we examined whether these changes are accompanied by morphological alterations of synapses. Chronically instrumented fetal sheep at 0.87 of gestation were treated either with isotonic saline (n=7) or 10 microg/h betamethasone (n=7) over 48 h administered directly to the fetal jugular vein. Paraffin sections of the frontal neocortex, caudate putamen and hippocampus were stained with a monoclonal antibody against synaptophysin, a specific membrane protein of presynaptic vesicles and quantified morphometrically. Synaptophysin-like immunoreactivity (synaptophysin-LI) showed a widespread granular pattern in the neuropil. Betamethasone exposure reduced synaptophysin-LI in the frontal neocortex, caudate putamen and hippocampus by 46.9, 41.0 and 55.4%, respectively, (P<0.05) that was not accompanied by irreversible neuronal damage. These results suggest that clinical doses of betamethasone have acute effects on presynaptic terminals in the fetal sheep brain that could contribute to the altered complexity of electrocortical function that we have shown previously to occur following fetal exposure to betamethasone.

Chromosomal mapping of human genes by radioactive hybridization of cDNAs to CEPH-YAC high density gridded filter sets

Chromosomal assignment of human transcribed sequences has been done mainly by high throughput genome analysis in specialized genome centres and, in a more classical fashion, by fluorescence in-situ hybridization (FISH) analysis. Not every laboratory has the ability to map cDNAs by FISH analysis. We here report a rapid mapping approach that is based on the hybridization of cDNA probes to high density gridded CEPH-YAC filters followed by subsequent computational analysis by database searches in the internet. Not only transcribed sequences but also genomic DNA could be subjected to this mapping approach. The presented approach allows to map human transcribed and genomic DNAs within 1-3 days and with a high level of resolution that will constantly increase in line with the incorporation of data deriving from high throughput genome mapping.

Cloning of the human homologue of the metastasis-associated rat C4.4A

We have previously described a rat metastasis-associated molecule, C4.4A, which has some common features with the uPAR. Because of its restricted expression in non-transformed tissues a search for the human homologue became of interest. Human C4.4A was cloned from a placental cDNA library. As in the rat, the human uPAR and the human C4.4A genes appear to belong to the same family. Both genes are located on chromosome 19q13.1-q13.2 and both molecules have a glycolipid anchor site and are composed of three extracellular domains. Only domains one and two of the human C4.4A and the uPAR protein show a significant degree of identity. Expression of the human C4.4A was observed by RT-PCR and Northern blotting in placental tissue, skin, esophagus and peripheral blood leukocytes, but not in brain, lung, liver, kidney, stomach, colon and lymphoid organs. Yet, tumors derived from the latter tissues frequently contained C4.4A mRNA. As demonstrated for malignant melanoma, C4.4A mRNA expression correlated with tumor progression. While nevi were negative and only a minority of primary malignant melanoma expressed C4.4A, all metastases were C4.4A-positive. Taking into account the high degree of homology between rat and human C4.4A, the conformity of the expression profiles and the association of rat C4.4A with tumor progression, human C4.4A might well become a prognostic marker and possibly a target of therapy.

MYCN amplification and 17q in neuroblastoma: evidence for structural association

MYCN oncogene amplification in neuroblastoma is statistically associated with gain of chromosome segment 17q21-qter. In neuroblastoma cell lines and primary tumors with MYCN amplification in the form of homogeneously staining regions (hsrs), juxtaposition of chromosome 17 material with MYCN sequences has occasionally been reported, raising the possibility of a physical affinity between MYCN and chromosome arm 17q. We used FISH to test for association between chromosome 17 segments and MYCN in eight neuroblastoma cell lines and two neuroblastoma primary tumors known to include hsrs. Evidence of an association was found in the chromosomes of both primary tumors; in one, a MYCN hsr was inserted into a structurally abnormal chromosome 17, in the other, an hsr in 16p was shown to be flanked by 17 material. In cell line NCG, hsrs in 4q and 16p were flanked by 17q material. These observations confirm the juxtaposition of 17q material with MYCN sequences in some neuroblastomas, and imply that there may be a physical or functional relationship between these two features in MYCN amplified neuroblastoma.

Topology of double minutes (dmins) and homogeneously staining regions (HSRs) in nuclei of human neuroblastoma cell lines

Amplification of the MYCN gene is a characteristic feature of many neuroblastomas and is correlated with aggressive tumor growth. Amplicons containing this gene form either double minutes (dmins) or homogeneously staining regions (HSRs). To study the nuclear topology of these tumor-specific and transcriptionally active chromatin structures in comparison to chromosome territories, we performed fluorescence in situ hybridization with a MYCN probe and various chromosome paint probes, confocal laser scanning microscopy, and quantitative three-dimensional image analysis. The dmins formed dot-like structures in interphase nuclei and were typically located at the periphery of complexly folded chromosome territories; dmins noted in the chromosome territory interior were often detected within an invagination of the territory surface. Interphase HSRs typically formed extremely expanded structures, which we have never observed for chromosome territories of normal and tumor cell nuclei. Stretches of HSR-chromatin often extended throughout a large part of the cell nucleus, but appeared well separated from neighboring chromosome territories. We hypothesize that dmins are located within the interchromosomal domain (ICD) space and that stretches of HSR-chromatin align along this space. Such a topology could facilitate access of amplified genes to transcription and splicing complexes that are assumed to localize in the ICD space.

MycN sensitizes neuroblastoma cells for drug-triggered apoptosis

BACKGROUND

Amplification of the MYCN gene is found in a large proportion of neuroblastomas and is associated with a poor prognosis.

PROCEDURE

To investigate the effect of ectopic MycN expression on the susceptibility of neuroblastoma cells to cytotoxic drugs, we used a human neuroblastoma cell line with tetracycline-controlled expression of MycN.

RESULTS

Neither conditional expression of MycN alone nor low drug concentrations induced apoptosis. However, MycN and cytotoxic drugs cooperated to induce cell death. Apoptosis triggered by MycN and doxorubicin was mediated by cleavage of caspases and involved activation of the CD95 system. MycN overexpression and cytotoxic drugs also synergized to induce p53 and Bax protein expression and to trigger mitochondrial permeability transition and cytochrome c release.

CONCLUSION

In that amplification of MYCN is considered an adverse prognostic factor, these findings suggest that dysfunctions in apoptosis pathways may be a mechanism by which MycN-induced apoptosis of neuroblastoma cells is inhibited.

Telomere length in different tissues of elderly patients

Telomeres are supposed to play a role in cellular aging and might contribute to the genetic background of human aging and longevity. During the past few years telomere length has been measured in various human tissues. However, very little is known about the individual telomere loss in different tissues from the same donor. Therefore we have measured telomere restriction fragment (TRF) length in three unrelated tissues (leukocytes, skin and synovial tissue) of nine elderly patients (age range 73-95 years old). Dependent on the tissue specific proliferation rate we have found significantly shorter telomeres (6546+/-519 bp, mean +/- S.D.) in leukocytes compared to skin (7792+/-596 bp, P<0.01) and synovial tissue (7910+/-420 bp, P<0.001). In general, we have observed an inverse relationship between donor age and TRF length which becomes significant in leukocytes (P=0.04, R(2)=0.49) and skin specimens (P=0.006, R(2)=0.81). Interestingly, linear correlations (P values between 0.017 and 0.038, R(2) values between 0.54 and 0.79) were also obtained on comparison of telomere length in each pair of two different tissues from the same donor without taking donor age into account. This suggests that genetic determination of the regulation of telomere length is tissue-independent. Furthermore, our results indicate that TRF measurement in easily accessible tissues such as blood could serve as a surrogate parameter for the relative telomere length in other tissues.

Effects of betamethasone administration to the fetal sheep in late gestation on fetal cerebral blood flow

Glucocorticoid administration to women at risk of preterm delivery to accelerate fetal lung maturation has become standard practice. Antenatal glucocorticoids decrease the incidence of intraventricular haemorrhage as well as accelerating fetal lung maturation. Little is known regarding side effects on fetal cerebral function. Cortisol and synthetic glucocorticoids such as betamethasone increase fetal blood pressure and femoral vascular resistance in sheep. We determined the effects of antenatal glucocorticoid administration on cerebral blood flow (CBF) in fetal sheep. Vehicle (n = 8) or betamethasone (n = 8) was infused over 48 h via the jugular vein of chronically instrumented fetal sheep at 128 days gestation (term 146 days). The betamethasone infusion rate was that previously shown to produce fetal plasma betamethasone concentrations similar to human umbilical vein concentrations during antenatal glucocorticoid therapy. Regional CBF was measured in 10 brain regions, using coloured microspheres, before and 24 and 48 h after onset of treatment, and during hypercapnic challenges performed before and 48 h after onset of betamethasone exposure. Betamethasone exposure decreased CBF in all brain regions measured except the hippocampus after 24 h of infusion (P < 0.05). The CBF decrease was most pronounced in the thalamus and hindbrain (45-50% decrease) and least pronounced in the cortical regions (35-40% decrease). It was mediated by an increase in cerebral vascular resistance (CVR, P < 0.05) and led to a decrease in oxygen delivery to subcortical and hindbrain structures of 30-40%, to 8.6 +/- 1.1 ml x (100 g)(-1) x min(-1), and 40-45 %, to 11.0 +/- 1.6 ml x 100 g(-1) x min(-1), respectively (P < 0.05). After 48 h of betamethasone treatment, the reduction in CBF was diminished to about 25-30 %, but was still significant in comparison to vehicle-treated fetuses in all brain regions except three of the five measured cortical regions (P < 0.05). CVR and oxygen delivery were unchanged in comparison to values at 24 h of treatment. The CBF increase in response to hypercapnia was diminished (P < 0.05). These observations demonstrate for the first time that glucocorticoids exert major vasoconstrictor effects on fetal CBF. This mechanism may protect the fetus against intraventricular haemorrhage both at rest and when the fetus is challenged. Betamethasone exposure decreased the hypercapnia-induced increase in CBF (P < 0.05) due to decreased cerebral vasodilatation (P < 0.05).

Elucidation of the genetic basis of the common 'intermediate metabolizer' phenotype for drug oxidation by CYP2D6

A subgroup of 10-15% of Caucasians are termed phenotypical 'intermediate metabolizers' of drug substrates of CYP2D6 because they have severely impaired yet residual in-vivo function of this cytochrome P450. Genotyping based on the currently known CYP2D6 alleles does not predict this phenotype satisfactorily. A systematic sequencing strategy through 1.6 kb of the CYP2D6 5'-flanking sequence revealed six mutations of which three were exclusively associated with the functional CYP2D6*2 allele (-1496 C to G; -652 C to T; and -590 G to A), two were associated with the nonfunctional *4 and with the functional *10-alleles (-1338 C to T and -912 G to A) and one (-1147 A to G) was seen in all *2, *4 and *10-alleles investigated. The -1496 C to G mutation was found to be polymorphic within CYP2D6*2 alleles. In a family study, the wild-type CYP2D6 *2[-1496 C] and the novel variant [-1496 G] allele co-segregated with lower and higher CYP2D6 in-vivo function, respectively, as shown by phenotyping using sparteine as probe drug. In a representative population sample selected for genotypes comprising one CYP2D6*2 and one non-functional allele, the median urinary metabolic ratio (MRs) for sparteine oxidation was 4.4-fold reduced in individuals with the variant allele (*2[-1496 G], MRs = 0.53, n = 27) compared with individuals lacking the mutation (*2[-1496 C], MRs = 2.33, n = 12; P < 0.0001). The mutation -1496 C to G has an estimated frequency of approximately 20% in the general population and allows establishment of a genotype for the identification of over 60% of intermediate metabolizers in Caucasian populations.

Developmental changes in the complexity of the electrocortical activity in foetal sheep

The foetal sheep brain develops organised sleep states from 115-120 d gestational age (dGA, term 150 dGA) alternating between REM and NREM sleep. We aimed to investigate whether maturation of REM or NREM sleep generating structures leads to the development of distinct sleep states. The electrocorticogram (ECoG) was recorded from five unanaesthetised chronically instrumented foetal sheep in utero and was analysed every 5th day between 115-130 dGA by two different non-linear methods. We calculated a non-linear prediction error which quantifies the causality of the ECoG and applied bispectral analysis which quantifies non-linear interrelations of single frequency components within the ECoG signal. The prediction error during REM sleep was significantly higher than during NREM sleep at each investigated age (P<0.0001) coincidental with poor organisation of the rhythmic pattern in the ECoG during REM sleep. At 115 dGA, organised sleep states defined behaviourally were not developed yet. The prediction error, however, showed already different states of electrocortical activity that were not detectable using power spectral analysis. The prediction error of the premature NREM sleep ECoG decreased significantly during emergence of organised sleep states between 115 and 120 dGA and continued to decrease after the emergence of distinct sleep states (P<0.05). The prediction error of the premature REM sleep ECoG did not change until 120 dGA and began to increase at 125 dGA (P<0.05). Using bispectral analysis, we showed couplings between delta waves (1.5-4 Hz) and frequencies in the range of spindle waves (4-8 and 8-12 Hz) during NREM sleep that became closer during development. The results show that maturation of ECoG synchronisation mediating structures is important for the development of organised sleep states. The further divergence of the prediction error of NREM and REM sleep after development of organised sleep states reveals continuous functional development. Thus, complementary application of non-linear ECoG analysis to power spectral analysis provide new insights in the collective behaviour of the neuronal network during the emergence of sleep states.

Fine mapping of distal 1p loci reveals TP73 at D1S468

In the present study we establish a FISH fine-map of 1p36.3 loci. This region is frequently altered in different types of human tumors suggesting the existence of cancer-related genes. Identification of cosmids carrying both D1S468 and TP73 sequences leads to the assignment of TP73 to the most frequently deleted locus in colon and breast cancer and integrates this gene in human genetic maps. Localization of other distal loci was determined as follows: distal-CDC2L1-D1Z2-D1S94-TP73/D1S468-D1 S1615-proximal. D1S1615, earlier reported as a telomeric sequence, is considerably more proximal than previously thought.

Chromosomal mapping of human genes by radioactive hybridization of cDNAs to Centre d'Etude du Polymorphisme humain high density gridded filter sets

Chromosomal assignment of human transcribed sequences has been done mainly by high throughput genome analysis in specialized genome centres and, in a more classical fashion, by fluorescence in-site hybridization (FISH) analysis. Not every laboratory has the ability to map cDNAs by FISH analysis. We here report a rapid mapping approach that is based on the hybridization of cDNA probes to high density gridded Centre d'Etude du Polymorphisme Humain filters followed by subsequent computational analysis by database searches in the internet. Not only transcribed sequences but also genomic DNA could be subjected to this mapping approach. The presented approach allows to map human transcribed and genomic DNAs within 1-3 days and with a high level of resolution that will constantly increase in line with the incorporation of data deriving from high throughput genome mapping.

Identification of the human cytochromes P450 involved in the oxidative metabolism of "Ecstasy"-related designer drugs

The human cytochrome P450 (CYP) isozymes catalyzing the oxidative metabolism of the widely abused amphetamine derivatives MDMA (N-methyl-3,4-methylenedioxyamphetamine, "Ecstasy"), MDE (N-ethyl-3, 4-methylenedioxyamphetamine, "Eve"), and MDA (3, 4-methylenedioxyamphetamine) were identified. Using a simplified non-extractive reversed-phase HPLC assay with fluorescence detection, biphasic Michaelis-Menten kinetics were obtained for formation of all three dihydroxyamphetamines in liver microsomes from a CYP2D6 extensive metabolizer subject. In contrast, no low K(m) component was detectable in microsomes from a poor metabolizer subject. Additional specific probes for CYP2D6 further confirmed this isozyme as the exclusive low K(m) component for demethylenation. P450-selective inhibitors applied to CYP2D6-inhibited microsomes and activity measurements in a series of recombinant P450s suggested CYP1A2 as the major high K(m) component with contributions by CYP2B6 and CYP3A4. Moreover, the relative CYP1A2 content of a panel of 12 human livers was weakly but significantly correlated to the high K(m) demethylenase activity (Spearman rank correlation coefficient [r(s)] = 0.58; P < 0.05). Microsomal maximal velocities for N-dealkylation were at least 7-fold lower than for demethylenation and were characterized by apparently monophasic kinetics. The most important isozyme for this reaction appeared to be CYP2B6, the microsomal content of which was found to be strongly correlated to N-deethylation of MDE (r(s) = 0.90; P < 0.001). We conclude that, in addition to CP2D6 as the sole high-affinity demethylenase, several other P450 isozymes have the capacity to contribute to microsomal oxidative metabolism of methylenedioxyamphetamines. This may be of particular importance in individuals genetically lacking functional CYP2D6.

Psychotropic drug use, falls and hip fracture in the elderly

The use of benzodiazepines (BZD) or other psychotropic agents is an established risk factor for falls and hip fractures. The evidence supporting this association has been based solely on history and/or prescription data. In a case-control study we monitored the intake of BZD, tricyclic antidepressants (TCA) and barbiturates in patients with hip fracture by serum analysis, and compared this measurement with drug history and prescription records. The serum was BZD positive in 41% of 82 community-dwelling patients; an equivalent by history and/or prescription records, however, was detected in only 18% (p < 0.0001). In contrast, in 82 age- and gender-matched community-dwelling control patients, there was only a minor discrepancy (3%) in BZD use between anamnestic (N = 19) and analytical (N = 21) data. In 23 patients admitted from nursing homes, a similar trend was visible (39% serum positive for BZD vs 26% by drug history). Barbiturate use (N = 2) could be neglected, and TCA intake was minor (N = 7); in each case both assessments were in accordance. In conclusion, in patients with hip fracture, BZD use is substantially more frequent than reported and previously assumed, pointing to an underestimated risk factor for this injury.

Retention of imprinting of the human apoptosis-related gene TSSC3 in human brain tumors

Genomic imprinting is the result of a gamete-specific modification leading to parental origin-specific gene expression in somatic cells of the offspring. Several embryonal tumors show loss of imprinting of genes clustered in human chromosome 11p15.5, an important tumor suppressor gene region, harboring several normally imprinted genes. TSSC3, a gene homologous to mouse TDAG51, implicated in Fas-mediated apoptosis, is also located in this region between hNAP2 and p57 (KIP2). TSSC3 is the first apoptosis-related gene found to be imprinted in placenta, liver and fetal tissues where it is expressed from the maternal allele in normal human development. This study investigated the imprinting status of TSSC3 in human normal, adult brain and in human neuroblastomas, medulloblastomas and glioblastomas. A polymorphism in exon 1 at position 54 was used to analyze the allelic expression of the TSSC3 gene by a primer oligo base extension (PROBE) assay using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). We found that the TSSC3 gene is not imprinted in human normal, adult brain and blood. In contrast, strong allelic bias resembling imprinting could be detected in most examined tumor specimens. The results demonstrate for the first time that the tumors under investigation are associated with a retention of imprinting of a potential growth inhibitory gene.

Identification and characterization of novel genes located at the t(1;15)(p36.2;q24) translocation breakpoint in the neuroblastoma cell line NGP

The distal portion of chromosome 1p is frequently deleted in several human cancers, suggesting the presence of one or more putative tumor suppressor genes on this chromosomal arm. In human neuroblastoma, a consistently deleted region at 1p36.1-p36.2 has been defined by comparison of molecular loss of heterozygosity (LOH) analyses. Recently we described the identification of a yeast artificial chromosome, YAC 927G4, that spans a translocation/duplication breakpoint within the minimally defined LOH region at 1p36.1-p36.2 in the neuroblastoma cell line NGP. Here we describe the identification of two overlapping P1 artificial chromosomes comprising 220 kb at the distal end of YAC 927G4, which we have used as hybridization probes under modified conditions to screen a composite, normalized cDNA library (IMAGE cDNA library). Hybridization screening resulted in the rapid and comprehensive identification of partial cDNAs of which a portion comprised two novel candidate genes, termed DNB1/ARPh and DNB5, which encode putative proteins of 1011 and 447 amino acids, respectively. The DNB1/ARPh gene, which was found to be ubiquitously expressed in human adult and fetal tissues, is highly related to the DRPLA gene, in which expansion of a CAG triplet appears to be causal in the dentatorubral and pallidolysian atrophy disease phenotype. The DNB5 sequence, in contrast, which is predominantly expressed in brain tissues and fetal kidney, failed to show any similarity to sequences in the public domain. A preliminary assessment of transcription and sequence of both genes in several neuroblastoma cell lines does not, thus far, support a causal role in neuroblastoma. However, further analyses are required to confirm these results.

[Quality assurance: the AO documentation at a peripheral hospital]

Follow-up of fracture treatment one year after surgery based on AO Documentation in a small, rural hospital in a region with many tourists is demanding. How many patients can be contacted and assessed at the one year follow-up? From 1.1.95 to 31.12.96 302 patients with 314 fractures were operated on and the results subsequently documented. 255 patients (84%) were assessed personally (221) or by an AO member or family doctor (34). 15 patients died before the appointment, 32 patients could not be contacted or their data was incomplete. To achieve this rate of follow-up, some internal organization in the hospital was necessary, as will be described in this paper. AO Documentation is an important tool for personal quality assurance, especially in small hospitals. Small hospitals might be interesting for the AO since their follow-up rate can be high due to a simple organization and a personal patient-doctor relationship.

Investigation of nonlinear ECoG changes during spontaneous sleep state changes and cortical arousal in fetal sheep

We examined the processes of cortical activation and deactivation of the fetal brain during spontaneous sleep state transitions and during central nervous processing of vibroacoustic stimulations (VASs) using nonlinear analysis of the electrocorticogram (ECoG). Tests of nonlinearity and a random shuffling routine revealed deterministic and nonlinear portions in the fetal ECoG. As common nonlinear measures are not applicable to nonstationary time series, we developed an algorithm to estimate the predictability of the ECoG in its time course by means of a point prediction error (PPE). The ECoG was recorded before and during VAS from the maternal abdominal surface in seven chronically instrumented fetal sheep at 0.8 of gestation. The PPE during REM sleep was significantly higher than during NREM sleep. VAS in NREM sleep resulted in an abrupt increase of the PPE not reaching the level of REM sleep. The steep increase of the PPE at onset and its slow decrease after cessation of the stimulus were very similar to the dynamics of spontaneous sleep state transitions, suggesting the involvement of the same cortical activating mechanisms. In conclusion, the stage and the time course of fetal brain activation and deactivation patterns can be clearly shown by PPE techniques. The PPE is a useful complement to spectral analysis. Both techniques describe different properties of the ECoG.

Epstein-Barr virus in pediatric patients after renal transplantation

BACKGROUND

Pediatric allograft recipients are at an increased risk for lymphotropic virus-associated disorders, particularly in association with primary EBV infection.

PATIENTS AND METHODS

Twenty-nine children, adolescents and young adults after renal transplantation were studied in comparison with a healthy young adult control group for evidence of primary, reactivated or chronic active EBV infection at two different time points.

RESULTS

Prevalence of antibodies against viral capsid antigen (VCA) was > or = 90% in both groups, whereas anti-Epstein-Barr nuclear antigen (EBNA) was detected only in 19 of 26 seropositive patients compared with seropositive controls (p = 0.01). Persistence of EBV DNA in leukocytes for > or = 6 months was observed in 11 seropositive patients (38%) and one control patient (p < 0.007) using nested polymerase chain reaction. In the transplant recipients, 3 cases of primary EBV infection and 3 cases of chronic active EBV infection were identified. One of these cases developed a non-Hodgkin lymphoma one year later.

CONCLUSION

The results suggest that determination of pretransplant antibody status in recipients, rapid detection of EBV infection in seronegative symptomatic recipients, and regular screening for persistent EBV DNA in patients at risk to develop post-transplantation lymphoproliferative disease should be performed.

Borderless teleradiology with CHILI

Teleradiology is one of the most evolved areas of telemedicine, but one of the basic problems which remains unsolved concerns system compatibility. The DICOM (Digital Imaging and Communications in Medicine) standard is a prerequisite, but it is not sufficient in all aspects. Examples of other currently open issues are security and cooperative work in synchronous teleconferences. Users without a DICOM radiological workstation would benefit from the ability to join a teleradiology network without any special tools. Drawbacks of many teleradiology systems are that they are monolithic in their software design and cannot be adapted to the actual user's environment. Existing radiological systems currently cannot be extended with additional software components. Consequently, every new application usually needs a new workstation with a different look and feel, which must be connected and integrated into the existing infrastructure. This paper introduces the second generation teleradiology system CHILI. The system has been designed to match both the teleradiology requirements of the American College of Radiology (ACR), and the functionality and usability needs of the users. The experiences of software developers and teleradiology users who participated in the first years of the clinical use of CHILI's predecessor MEDICUS have been integrated into a new design. The system has been designed as a component-based architecture. The most powerful communication protocol for data exchange and teleconferencing is the CHILI protocol, which includes a strong data security concept. The system offers, in addition to its own secure protocol, several different communication Methods: DICOM, classic e-mail, Remote Copy functions (RCP), File Transfer Protocol (FTP), the internet protocols HTTP (HyperText Transfer Protocol) and HTTPS (HyperText Transfer Protocol Secure),and CD-ROMs for off-line communication. These transfer METHODS allow the user to send images to nearly anyone with a computer and a network. The drawbacks of the non-CHILI protocols are that teleconferences are not possible, and that the user must take reasonable precautions for data privacy and security. The CHILI PlugIn mechanism enables the users or third parties to extend the system capabilities by adding powerful image postprocessing functions or interfaces to other information systems. Suitable PlugIns can be either existing programs, or dedicated applications programmed with interfaces to the CHILI components. The developer may freely choose programming languages and interface toolkits. The CHILI architecture is a powerful and flexible environment for Picture Archiving and Communications Systems (PACS)and teleradiology. More than 40 systems are currently running in clinical routine in Germany. More than 300,000 images have been distributed among the communication partners in the last two years. Feedback and suggestions from the users influenced the system architecture by a great extent. The proposed and implemented system has been optimized to be as platform independent, open, and secure as possible.