Developing human biomonitoring as a 21st century toolbox within the European exposure science strategy 2020-2030

Human biomonitoring (HBM) is a crucial approach for exposure assessment, as emphasised in the European Commission's Chemicals Strategy for Sustainability (CSS). HBM can help to improve chemical policies in five major key areas: (1) assessing internal and aggregate exposure in different target populations; 2) assessing exposure to chemicals across life stages; (3) assessing combined exposure to multiple chemicals (mixtures); (4) bridging regulatory silos on aggregate exposure; and (5) enhancing the effectiveness of risk management measures. In this strategy paper we propose a vision and a strategy for the use of HBM in chemical regulations and public health policy in Europe and beyond. We outline six strategic objectives and a roadmap to further strengthen HBM approaches and increase their implementation in the regulatory risk assessment of chemicals to enhance our understanding of exposure and health impacts, enabling timely and targeted policy interventions and risk management. These strategic objectives are: 1) further development of sampling strategies and sample preparation; 2) further development of chemical-analytical HBM methods; 3) improving harmonisation throughout the HBM research life cycle; 4) further development of quality control / quality assurance throughout the HBM research life cycle; 5) obtain sustained funding and reinforcement by legislation; and 6) extend target-specific communication with scientists, policymakers, citizens and other stakeholders. HBM approaches are essential in risk assessment to address scientific, regulatory and societal challenges. HBM requires full and strong support from the scientific and regulatory domain to reach its full potential in public and occupational health assessment and in regulatory decision-making.

Stochastic Fluctuations of Low-Energy Cosmic Rays and the Interpretation of Voyager Data

Data from the Voyager probes have provided us with the first measurement of cosmic ray intensities at MeV energies, an energy range that had previously not been explored. Simple extrapolations of models that fit data at GeV energies, e.g., from AMS-02, however, fail to reproduce the Voyager data in that the predicted intensities are too high. Oftentimes, this discrepancy is addressed by adding a break to the source spectrum or the diffusion coefficient in an ad hoc fashion, with a convincing physical explanation yet to be provided. Here, we argue that the discrete nature of cosmic ray sources, which is usually ignored, is instead a more likely explanation. We model the distribution of intensities expected from a statistical model of discrete sources and show that its expectation value is not representative but has a spectral shape different from that for a typical configuration of sources. The Voyager proton and electron data are however compatible with the median of the intensity distribution.

A Statistically Representative Atlas for Mapping Neuronal Circuits in the Drosophila Adult Brain

Imaging the expression patterns of reporter constructs is a powerful tool to dissect the neuronal circuits of perception and behavior in the adult brain of Drosophila, one of the major models for studying brain functions. To date, several Drosophila brain templates and digital atlases have been built to automatically analyze and compare collections of expression pattern images. However, there has been no systematic comparison of performances between alternative atlasing strategies and registration algorithms. Here, we objectively evaluated the performance of different strategies for building adult Drosophila brain templates and atlases. In addition, we used state-of-the-art registration algorithms to generate a new group-wise inter-sex atlas. Our results highlight the benefit of statistical atlases over individual ones and show that the newly proposed inter-sex atlas outperformed existing solutions for automated registration and annotation of expression patterns. Over 3,000 images from the Janelia Farm FlyLight collection were registered using the proposed strategy. These registered expression patterns can be searched and compared with a new version of the BrainBaseWeb system and BrainGazer software. We illustrate the validity of our methodology and brain atlas with registration-based predictions of expression patterns in a subset of clock neurons. The described registration framework should benefit to brain studies in Drosophila and other insect species.

Automatic Segmentation of Drosophila Neural Compartments Using GAL4 Expression Data Reveals Novel Visual Pathways

Identifying distinct anatomical structures within the brain and developing genetic tools to target them are fundamental steps for understanding brain function. We hypothesize that enhancer expression patterns can be used to automatically identify functional units such as neuropils and fiber tracts. We used two recent, genome-scale Drosophila GAL4 libraries and associated confocal image datasets to segment large brain regions into smaller subvolumes. Our results (available at https://strawlab.org/braincode) support this hypothesis because regions with well-known anatomy, namely the antennal lobes and central complex, were automatically segmented into familiar compartments. The basis for the structural assignment is clustering of voxels based on patterns of enhancer expression. These initial clusters are agglomerated to make hierarchical predictions of structure. We applied the algorithm to central brain regions receiving input from the optic lobes. Based on the automated segmentation and manual validation, we can identify and provide promising driver lines for 11 previously identified and 14 novel types of visual projection neurons and their associated optic glomeruli. The same strategy can be used in other brain regions and likely other species, including vertebrates.

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Genome-scale enhancer expression patterns can be used to predict brain structure

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Automated clustering of images finds known structures such as olfactory glomeruli

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Results identify GAL4 lines with strong expression in the predicted structures

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We validate novel predictions to reveal previously undescribed optic glomeruli

Acoustic radiation force impulse imaging for non-invasive assessment of liver fibrosis in chronic hepatitis B

Acoustic radiation force impulse (ARFI) imaging is a novel ultrasound-based elastography method that is integrated in a conventional ultrasound machine. It might provide an alternative method to transient elastography for the noninvasive assessment of liver fibrosis. While previous studies have shown comparable diagnostic accuracy of ARFI to transient elastography in chronic hepatitis C, the aim of the present prospective multicenter study was to evaluate ARFI for the assessment of liver fibrosis in chronic hepatitis B. ARFI imaging involves the mechanical excitation of tissue using short-duration acoustic pulses to generate localized displacements in tissue. The displacements result in shear-wave propagation which is tracked using ultrasonic, correlation-based methods and recorded in m/s. In the present international prospective study, patients infected with chronic hepatitis B received ARFI imaging, blood tests and if available transient elastography. The results were compared to liver biopsy as reference method analysed by a central pathologist. In 92 of 114 patients, a comparison of ARFI with transient elastography was possible. ARFI imaging and transient elastography correlated significantly with histological fibrosis stage. The diagnostic accuracy expressed as areas under ROC curves for ARFI imaging and transient elastography was 0.75 and 0.83 for the diagnosis of significant fibrosis (F ≥ 2), 0.93 and 0.94 for the diagnosis of severe fibrosis (F ≥ 3), and 0.97 and 0.93 for the diagnosis of liver cirrhosis, respectively. No significant difference was found between ARFI and transient elastography. ARFI imaging is a reliable ultrasound-based method for the assessment of advanced stages of liver fibrosis in chronic hepatitis B.

Simultaneous manifestation of acute myocardial infarction and nephrotic syndrome

This report describes the simultaneous manifestation of ischemic heart disease and nephrotic syndrome in a 37-year-old woman presenting with acute anterior myocardial infarction. Symptoms of nephrotic syndrome, such as facial and peripheral edema accompanied by proteinuria and hyperlipidemia, and onset of severe retrosternal pain developed within 24 h. Coronary angiography revealed a complete thrombotic occlusion of the proximal portion of the left anterior descending artery with no evidence of arteriosclerotic lesions. Histologic examination of renal biopsy, including electron microscopy, revealed evidence of minimal change glomerulonephritis. Ultrastructural studies demonstrated widespread effacement of epithelial foot processes. Elevated levels of circulating fibrinogen appeared to be an important factor for the hypercoagulable state in this patient, suggesting a causative relationship between coronary thrombosis and nephrotic syndrome.

Genomic and phenotypic changes of Campylobacter jejuni strains after passage of the chicken gut

The ability to colonize the chicken gut was determined for 17 Campylobacter jejuni strains of human and bovine origin. The level of colonization varied according to the strain used for experimental infection. Two Campylobacter isolates from patients suffering from gastroenteritis were found in the group of non-colonizing strains, suggesting that other reservoirs as poultry are also important sources of human Campylobacter infections. Bovine Campylobacter isolates can also effective colonize the chicken intestine and may be a source for poultry infection. The invasion ability of the strains as determined in the cell culture model using Caco-2 cells correlates with their colonization capacity in the chicken gut. The genomic and phenotypic stability of the selected strains were evaluated by analysis of their pulsed-field gel electrophoresis (PFGE) patterns, flaA-typing and in vitro determination of motility, adhesion and invasion abilities after colonizing chickens for up to 21 days. Changes were identified in flaA-types of six isolates and three isolates from chicken showed different patterns by PFGE using SmaI or KpnI as restriction enzymes. One isolate showed phenotypic differences after in vivo passage which were seen in enhancement of adherence to eukaryotic cells, decrease of motility and changes in morphology. These phenotypic changes were not associated with the observed genomic instabilities.

Analysis of microsatellite instability in colorectal carcinoma by microfluidic-based chip electrophoresis

Microsatellite analysis is an important tool in clinical research and molecular diagnostics because microsatellite instability (MSI) occurs frequently in various types of cancer. Approximately 10–15% of colorectal, gastric and endometrial carcinomas are associated with MSI, and this has an impact on clinical prognosis. The microsatellite loci Bat25, Bat26, D2S123, D5S346 and D17S250, recommended by the Bethesda guidelines, were analysed by microfluidic-based on-chip electrophoresis in 40 cases of colon carcinoma with known MSI status. In all cases, microfluidic separation of the PCR amplicons resulted in highly resolved, distinct patterns of each of the five microsatellite loci. Detection of MSI could be demonstrated by microsatellite-loci-associated, well-defined deviations in the electropherogram profiles of tumour and non-tumour material, and confirmed the classification of MSI cases performed by conventional technology. In conclusion, microfluidic chip technology is a simple and reliable approach for MSI detection that allows label-free and very fast analysis of microsatellite amplicons.

Differential Flo8p-dependent regulation of FLO1 and FLO11 for cell-cell and cell-substrate adherence of S. cerevisiae S288c

Cell–cell and cell–surface adherence represents initial steps in forming multicellular aggregates or in establishing cell–surface interactions. The commonly used Saccharomyces cerevisiae laboratory strain S288c carries a flo8 mutation, and is only able to express the flocculin-encoding genes FLO1 and FLO11, when FLO8 is restored. We show here that the two flocculin genes exhibit differences in regulation to execute distinct functions under various environmental conditions. In contrast to the laboratory strain Σ1278b, haploids of the S288c genetic background require FLO1 for cell–cell and cell–substrate adhesion, whereas FLO11 is required for pseudohyphae formation of diploids. In contrast to FLO11, FLO1 repression requires the Sin4p mediator tail component, but is independent of the repressor Sfl1p. FLO1 regulation also differs from FLO11, because it requires neither the KSS1 MAP kinase cascade nor the pathways which lead to the transcription factors Gcn4p or Msn1p. The protein kinase A pathway and the transcription factors Flo8p and Mss11p are the major regulators for FLO1 expression. Therefore, S. cerevisiae is prepared to simultaneously express two genes of its otherwise silenced FLO reservoir resulting in an appropriate cellular surface for different environments.

The Saccharomyces Homolog of Mammalian RACK1, Cpc2/Asc1p, Is Required for FLO11-dependent Adhesive Growth and Dimorphism

Nutrient starvation results in the interaction of Saccharomyces cerevisiae cells with each other and with surfaces. Adhesive growth requires the expression of the FLO11 gene regulated by the Ras/cAMP/cAMP-dependent protein kinase, the Kss1p/MAPK, and the Gcn4p/general amino acid control pathway, respectively. Proteomics two-dimensional DIGE experiments revealed post-transcriptionally regulated proteins in response to amino acid starvation including the ribosomal protein Cpc2p/Asc1p. This putative translational regulator is highly conserved throughout the eukaryotic kingdom and orthologous to mammalian RACK1. Deletion of CPC2/ASC1 abolished amino acid starvation-induced adhesive growth and impaired basal expression of FLO11 and its activation upon starvation in haploid cells. In addition, the diploid Flo11p-dependent pseudohyphal growth during nitrogen limitation was CPC2/ASC1-dependent. A more detailed analysis revealed that a CPC2/ASC1 deletion caused increased sensitivity to cell wall drugs suggesting that the gene is required for general cell wall integrity. Phosphoproteome and Western hybridization data indicate that Cpc2p/Asc1p affected the phosphorylation of the translational initiation factors eIF2 alpha and eIF4A and the ribosome-associated complex RAC. A crucial role of Cpc2p/Asc1p at the ribosomal interface coordinating signal transduction, translation initiation, and transcription factor formation was corroborated.

[Epithelial-mesenchymal transition of biliary epithelial cells in advanced liver fibrosis]

The conversion of epithelial cells in a mesenchymal cell type is called "epithelial-mesenchymal-transition" (EMT). This process is defined by a loss of epithelial specific characteristics such as cell adhesion, polarity and a reorganization of cytoskeletal proteins. EMT has been shown to be involved in progression of cancer and in obstructive renal fibrosis. In this study we analyzed liver tissues in a bile-duct ligation model of rats and human liver biopsies with cholestatic fibrosis and chronic hepatitis c infection to determine if biliary epithelial cells undergo phenotypical and functional changes during chronic injury.

METHODS

Liver tissue of rats and human patients was examined by immunohistochemistry using antibodies against epithelial and mesenchymal specific targets as well as molecules of potentially activated signaling pathways. To study contribution of biliary epithelial cells in extracellular matrix production we performed laser microdissection combined with real-time PCR.

RESULTS

Bile duct ligation in rats induced a prominent biliary epithelial proliferation and a pronounced expression of vimentin was observed in biliary epithelial cells, whereas no vimentin expression was detectable in bile duct cells of sham operated rats. In human liver biopsies from patients with cholestatic fibrosis and chronic hepatitis c infection a prominent biliary expression of vimentin could be shown. Despite this, epithelial marker proteins were still detectable. Further, we observed collagen I mRNA expression in laser microdissected bile ducts.

CONCLUSION

Biliary epithelial cells show cytoskeletal rearrangements during chronic liver injury towards a mesenchymal phenotype. The detection of collagen I mRNA in bile duct cells suggests that they might participate in extracellular matrix production.

Yeast Gcn4p stabilization is initiated by the dissociation of the nuclear Pho85p/Pcl5p complex

Protein stability of the c-jun-like yeast bZIP transcriptional activator Gcn4p is exclusively controlled in the yeast nucleus. Phosphorylation by the nuclear Pho85p cyclin-dependent protein kinase, a functional homolog of mammalian Cdk5, initiates the Gcn4p degradation pathway in complex with the cyclin Pcl5p. We show that the initial step in Gcn4p stabilization is the dissociation of the Pho85p/Pcl5p complex. Pcl7p, another nuclear and constantly present cyclin, is required for Gcn4p stabilization and is able to associate to Pho85p independently of the activity of the Gcn4p degradation pathway. In addition, the nuclear cyclin-dependent Pho85p kinase inhibitor Pho81p is required for Gcn4p stabilization. Pho81p only interacts with Pcl5p when Gcn4p is rapidly degraded but constitutively interacts with Pcl7p. Our data suggest that Pcl7p and Pho81p are antagonists of the Pho85p/Pcl5p complex formation in a yet unknown way, which are specifically required for Gcn4p stabilization. We suggest that dissociation of the Pho85p/Pcl5p complex as initial step in Gcn4p stabilization is a prerequisite for a shift of equilibrium to an increased amount of the Pho85p/Pcl7p complexes and subsequently results in decreased Gcn4p phosphorylation and therefore increased stability of the transcription factor.

Development of a cell culture assay for the quantitative determination of vaccination-induced antibodies in rabbit sera against Clostridium perfringens epsilon toxin and Clostridium novyi alpha toxin

Cell culture assays are possible alternatives to replace in vivo neutralization tests currently required for potency testing of clostridial vaccines. Cell culture assays based on the MDCK cell line and the Vero cell line which are sensitive to the Clostridium (C.) perfringens type D epsilon toxin and Clostridium novyi type B alpha toxin, respectively, were developed, and the test conditions were standardized. The antibody titres of vaccinated rabbits measured in vitro were compared with the results of current test procedures recommended by European Pharmacopoeia. The correlation coefficients calculated were significant for all sera tested. The cell culture assays proved to be sensitive, specific, reproducible and reliable. Therefore, these cell culture assays could be suitable in vitro alternatives to the in vivo mouse neutralization experiments required for potency tests of clostridial vaccines, but further validation studies are necessary.

PCR detection of virulence-associated genes in Campylobacter jejuni strains with differential ability to invade Caco-2 cells and to colonize the chick gut

In this study, the presence of 20 putative virulence genes was examined in 11 Campylobacter jejuni isolates with different colonization and invasion abilities as determined in a chick colonization model and on Caco-2 cells, respectively. The majority of the genes were detected in all strains. Among them, there were genes of the flagellar secretion apparatus like flhA, flhB, flgB, flgE2, the flagellin genes flaA and flaB, invasion-associated genes like ciaB and iamA, the cytotoxin genes cdtA-C, the adhesion related gene cadF, and some genes involved in the colonization process (docA, docB). The plasmid gene virB11 could not be detected in any strain. Specific differences between the isolates were observed only in genes cgtB and wlaN involved in lipo-oligosaccharide (LOS) biosynthesis. The gene cgtB was only detectable in three of five strains with strong colonization and invasion abilities. Probably, wlaN can overcome the lack of cgtB in the two cgtB- isolates.

Determination of a reference value for N(G), N(G)-dimethyl-L-arginine in 500 subjects

BACKGROUND

Asymmetric dimethylarginine (ADMA) acts as an endogenous inhibitor of NO-synthase. In the last years ADMA has emerged as a cardiovascular risk factor. The aim of this study was to determine a reference value for ADMA.

METHODS

Plasma samples of 500 healthy subjects in the 19-75 year age group were analyzed. Exclusion criteria from this study were smoking, any known significant disease, body-mass-index (BMI) above 30 kg m(-2), elevated plasma lipid levels, impaired renal function, hypertension, and intake of any medication. The ADMA levels were determined by ELISA, (DLD Diagnostics, Hamburg, Germany).

RESULTS

Mean ADMA plasma concentration of the total population was 0.69 micromol L(-1) (SD 0.20) and 95% of the measured values were in the range from 0.36 micromol L(-1) to 1.17 micromol L(-1). Women below 50 years of age had lower ADMA levels than men below 50 years of age [0.62 (0.17) micromol L(-1) vs. 0.69 (0.19) micromol L(-1); P = 0.001] and woman above 50 years of age had higher ADMA levels than men above 50 years of age [0.80 (0.22) micromol L(-1) vs. 0.73 (0.20) micromol L(-1); P = 0.036]. A regression analysis of ADMA levels and age was performed for each sex. The regression factor was r = 0.444 for women in a squared regression model (P < 0.001) and r = 0.212 for men in a linear regression model (P < 0.001).

CONCLUSION

The study was able to define a reference value for ADMA plasma levels with 0.36-1.17 micromol L(-1) and found sex dependent correlations between ADMA and age. Women showed a significant increase in ADMA plasma levels with onset of menopause.

Correlation between invasion of Caco-2 eukaryotic cells and colonization ability in the chick gut in Campylobacter jejuni

In an in vitro cell culture model using Caco-2 cells the adhesion and invasion properties of 11 Campylobacter (C.) jejuni isolates of different origin were studied. Additionally, we investigated the colonization ability of the strains in a chick model. Virtually, all C. jejuni showed cell adherence in the in vitro assay, but there were large differences in the invasion frequencies among the Campylobacter isolates. The colonization ability in the chick gut also differed markedly and enabled the formation of three groups: non-colonizing, weak or delayed colonization and strong colonization ability. On this occasion, we found a putative correlation between invasion of Caco-2 cells and colonization in the chick gut. Non-colonizers are not invasive or only have small invasion indexes. Strains which colonize weakly or exhibit delayed colonization have a medium invasion index and strong colonizers show markedly higher values of this parameter. The characterization of the flagellin gene of the used C. jejuni strains resulted in eight flaA types. There was no association between flaA type and invasion or colonization ability in the chick gut.

[Identification and differentiation of Campylobacter fetus subspecies by PCR]

The species Campylobacter (C.) fetus is divided into the subspecies venerealis and fetus, which differ in epidemiology and clinical importance. The differences between these subspecies make an accurate distinction essential. Differentiation of C. fetus by traditional microbiological methods is only based on two reactions (tolerance to glycin, Na selenite reduction), in which C. fetus ssp. venerealis reacts negatively. However, the value of both reactions is limited. We used a specific PCR-based assay for identifying and differentiating the two C. fetus subspecies, which was recently developed by HUM et al. (1997). In this assay, a 764 bp amplicon is produced using primers MG3F and MG4R for both subspecies of C. fetus. In contrast to HUM et al. (1997), this amplicon was approximately 200 bp smaller. This discrepancy can't be explained. Afterwards, the primers VenSF and VenSR are used for differentiation. The identification of the sub-species venerealis is based on the presence of a 142 bp amplicon, which is not formed with subspecies fetus. The type strains of both C. fetus subspecies were used as positive controls. Non-specific reactions were not observed. In this PCR assay, 73 field strains were investigated (among them 24 C. fetus ssp. veneralis, 26 C. fetus ssp. fetus). In these investigations, the method has proved its diagnostic suitability. The results of the traditional microbiological differentiation of the C. fetus field strains could be confirmed by the PCR assay. In future, the traditional phenotypic characterization of C. fetus subspecies remains indispensable, but this PCR assay constitutes a valuable method for the confirmation of these results.

[Colonisation studies using Campylobacter jejuni in chicks]

White Leghorn chicks used in this study were hatched from specific pathogen-free eggs. The colonizing capability of Campylobacter (C.) jejuni strains was investigated in 6 experiments. The formation of specific antibodies associated to colonization was also detected. In each experiment, day of hatch chicks were randomly separated into three groups of 24 birds each: two groups colonized experimentally and one control group. Chicks were reared on the floor in three separated, adjacent rooms with sterilized wood shavings as litter. At 2 or 8 days of age, respectively, the chicks in the experimentally colonized groups received between 3.3 x 10(7) and 2.0 x 10(8) colony-forming units (CFU) of C. jejuni via oesophageal gavage. Furthermore, 7, 14, 21, 28, 42 and 56 days after inoculation, 4 chicks of each group were sacrificed by cervical dislocation, at which time blood, liver and faeces were collected for processing. Serum was centrifuged and Campylobacter-specific IgG, IgA and IgM antibodies were measured by an indirect enzyme-linked immunosorbent assay (ELISA). Altogether, the colonizing capability of 11 C. jejuni strains was examined. Surprisingly, there were large differences between the C. jejuni isolates. After these experiments, we could divide the isolates into three groups. 4 out of 11 isolates could not be reisolated, 2 isolates caused weak or delayed colonization and 5 C. jejuni produced strong, long-lasting colonization. In the first days of life (9 days), the C. jejuni-free SPF chicks (control animals) had high IgG titres in sera, which decreased markedly up to the age of 15 days. During the experiments the IgM and IgA titres remained nearly at the same level, i.e., the amounts of maternal antibodies were low and there was no evidence for antibody formation in the chicks themselves. Two- and 8-day-old chicks were inoculated with C. jejuni strain Penner 1. Two-day-old chicks were colonized 3 weeks after inoculation. In comparison with these animals, 8-day-old chicks were colonized already 2 weeks after inoculation. There is the assumption, that the higher maternal antibodies in 2-day-old chicks could be responsible for this delay. In chicks the C. jejuni colonization resulted in a marked IgG (but not IgM and IgA) increase. Apparently, there is a positive relationship between the counts of this pathogen in caeca and the IgG increase.

[The use of the toxin binding inhibition test for potency testing of Clostridium novyi type B alpha toxoid vaccines]

The toxin binding inhibition test (ToBI) were developed for potency testing of C. novyi type B alpha toxoid containing veterinary vaccines to replace the currently used toxin neutralisation test in mice (TNT). The antitoxin titres of rabbit sera (AN-, HV- and SP sera) were determined with ToBI using the international reference serum with known antitoxin titre. In order to show the validity of the methods, the results were compared with those of the manufacturers/regulatory authorities and correlation coefficients were calculated. The correlation coefficients were r = 0.93 (AN sera), r = 0.73 (HV sera) and r = 0.85 (SP sera). All correlations were statistically significant. The specificity of the methods could be proved using heterologous antisera. The results of the ToBI were reproducible. Thus, the ToBI offers a suitable in vitro method for the determination of the antitoxin titre of rabbit antisera as an alternative to the toxin neutralisation in mice for potency testing of vaccines containing C. novyi type B alpha toxoid.

[Development of in vitro methods for the potency testing of clostridial vaccines]

Cell culture assays, using the MDCK cell line was confirmed as being sensitive to the C. perfringens epsilon toxin and VERO cell line to the C. novyi type B alpha toxin. Cell culture assays using these cells were developed and the test conditions were standardised. The antitoxin titres of rabbit antisera were calculated and compared with those of the manufacturers. The correlation coefficients between in vitro and in vivo method were calculated and were significant. The cell culture assay offers a valid in vitro alternative to the animal experiments for the titration of sera generated in the course of potency tests of clostridial vaccines.

Retrocardiac arteriovenous malformation causing recurrent cerebral ischemia

A 28-year-old woman had been suffering from recurrent cerebral embolizations for almost 9 years. A retrocardiac arteriovenous malformation was identified as the source of emboli. It was supplied by chest wall veins and the right upper pulmonary vein, connected to the back wall of the left atrium and a possibly aberrant hepatic vein originating from the abdomen. The aneurysm was resected and all supplying veins ligated. The vein from below the diaphragm was implanted into the right atrium. Her postoperative course was uncomplicated. Long-term follow-up free from cerebrovascular events.

Detection of Clostridium novyi type B alpha toxin by cell culture systems

Ten permanent cell lines were examined for their reaction to the Clostridium novyi alpha toxin. The action of the toxin was determined after 3 days by microscopic examination and the MTT assay. The alpha toxin exhibited the strongest effect on ESH-L cells rather than other cell lines. Vero and SFT-R cells reacted in a comparable way, but less sensitively. We were able to show that the cytopathic effect on the three types of cells was neutralised by the international standard for gas gangrene antitoxin (C. novyi) but in no case by heterologous antisera. Our results have shown that the three cell lines were specific indicators for the detection of the cytopathic effect of alpha toxin. The cytopathic effect can be measured reproducibly by the cell culture assay used. These results are suitable as the starting point for the development of the neutralisation test using cell cultures.

[Computer assisted training of attention and concentration with healthy children]

The intention of this study was to analyze in how far a computer assisted training for brain damaged adults can be used for the practice with children. Healthy children of different ages were trained with this attention and concentration programme. The results should help to adapt the training programme for the use in brain damaged children. Age-groups differed significantly in level of performance. Data showed that in comparison to Kindergarten-children, first-grade children showed a higher benefit from the training. Implications for modifications of the training-programme are discussed. Other parameter of performance (reaction-time, errors) in relation to school age provide clues to the distribution of structure of difficulty in the programmes. A questionnaire assessing motivation before and during the training, intelligibility of the task, feasibility of the computer and adequacy of the test in children showed that sustained motivation can be achieved provided the training is used in an adaptive way. Thereby demotivating with too easy tasks as well as frustration caused by difficult tasks can be avoided. In general, there was good acceptance of the computerised cognitive training. The presence of a therapist during every training session proved to be necessary in children under the age of 6 years.

Formation of cytotoxins by enteric Campylobacter in humans and animals

Campylobacter (C.) jejuni from persons suffering from diarrhoea, from organs of poultry, C. jejuni and C. fetus ssp. fetus from the gastrointestinal tract of calves and adult cattle as well as a number of reference strains were examined for cytotoxin formation in a CHO-K1 cell culture test. During evaluation, three morphologically different pictures were observed. The first cytotoxin caused a formation of strikingly large, rounded or polymorphic and elongated cells which was associated with reduced growth. The progressive morphological changes corresponded to those described for the Cytolethal Distending Toxin (CLDT) and were assigned to it. The second cytotoxin produced a rounding of cells without a change in their size while at the same time, growth was reduced. In analogy to CLDT, this toxin was termed Cytolethal Rounding Toxin (CLRT). A third morphological picture consisted of cell changes characterized by enlarged polymorphic as well as by small rounded cells. These cell changes were considered as being distinct from the above mentioned ones and referred to as CLTD/CLRT effect. In none of the 39 Campylobacter strains isolated from humans and calves with diarrhoea, a noteworthy cytotonic activity could be detected that would indicate the presence of an enterotoxin.

Detection and characterization of two cytotoxins produced by Campylobacter jejuni strains

Campylobacter jejuni strains are able to produce at least two different cytotoxins called "cytolethal distending toxin" (CLDT) and "cytolethal rounding toxin" (CLRT). In this study, we investigated the corresponding changes in CHO-K1 cells using the cell counter and analyzer system CASY 1. Determination of the cell volume after toxin treatment of the cells is a useful criterion for differentiation between the cytotoxic activities produced by Campylobacter strains. Incubation of the cells with crude CLDT resulted in a decrease in the cell count combined with a dramatic increase of the mean cell volume in comparison to the control culture. A decrease in the cell count was also seen as a response to CLRT preparations, while this toxin had no effect on the mean cell volume determined. It was shown that only CLDT caused histone-associated DNA fragments in the cytoplasm of CHO-K1 cells indicating an apoptotic pathway of cell death. In addition, the polymerase chain reaction (PCR) was employed to screen Campylobacter strains for the presence of the cdtB gene sequence, which was detectable in all strains investigated.

Acute renal failure following cardiac surgery is reverted by administration of Urodilatin (INN: Ularitide)

Acute renal failure (ARF) is a serious complication following cardiac surgery. This first controlled study was undertaken to verify, if Urodilatin (URO) infusion can revert incipient oliguric ARF after cardiac surgery. We conducted a randomized, double blind trial comparing 7 URO (20 ng/kg/min) with 7 placebo patients. Inclusion criterion was oliguria/anuria (< 0.5 ml/kg/hour) refractory to conventional treatment including administration of dopamine and furosemide. No patient in the URO treated group, but 6 patients in the placebo group had to be hemofiltered or hemodialyzed (p < 0.005) during the 7 day treatment period. In the URO group all 7 patients demonstrated a rapid recovery of diuresis after 2 - 8 hours of treatment that persisted throughout the treatment period. In contrast, placebo treated patients remained oliguric. Serum creatinine (SC) decreased in URO treated patients. No adverse effects were observed during URO administration. After termination of URO, 2 patients underwent hemodialysis for elevated blood urea nitrogen (BUN) values. In the postoperative follow-up period of 60 days, 4 out of 7 placebo treated patients died while still on hemodialysis. In contrast, all URO patients survived. URO is an effective drug to reverse oliguric ARF following cardiac surgery. Prolonged renal failure and renal replacement therapy can be avoided.

[Detection of Clostridium perfringens toxins on cell cultures]

An important prerequisite for the possible application of cell culture systems as an in vitro method for the potency test of C. perfringens vaccines is the detection of cytotoxic effects of non-neutralized toxins on cell cultures. For this purpose eight cell lines were investigated in terms of the sensitivity to toxins using microscopy and the MTT assay. The results suggest that the MDCK cell line is a sensitive and specific detection system for epsilon-toxin. The VERO cell line is a suitable indicator for the detection of beta-toxin. Another task was the selection of a sensitive method for the analysis of cytotoxic effects of the toxins used. The neutral red and the tetrazolium-(MTT)-assays were compared for three cell lines (MDCK, FBTR, MA 104). The MTT assay was proved to be the optimal test system under our conditions.