A structural MRI study in monozygotic twins concordant or discordant for attention/hyperactivity problems: evidence for genetic and environmental heterogeneity in the developing brain.

Several structural brain abnormalities have been reported in patients with Attention Deficit Hyperactivity Disorder (ADHD). However, the etiology of these brain changes is still unclear. To investigate genetic and environmental influences on ADHD related neurobiological changes, we performed Voxel-Based Morphometry on MRI scans from monozygotic (MZ) twins selected from a large longitudinal population database to be highly concordant or highly discordant for ratings on the Child Behavior Checklist Attention Problem scale (CBCL-AP). Children scoring low on the CBCL-AP are at low risk for ADHD, whereas children scoring high on this scale are at high-risk for ADHD. Brain differences between concordant high-risk twin pairs and concordant low-risk twin pairs likely reflect the genetic risk for ADHD; brain differences between the low-risk and high-risk twins from discordant MZ twin pairs reflect the environmental risk for ADHD. A major difference between comparisons of high and low-risk twins from concordant pairs and high/low twins from discordant pairs was found for the prefrontal lobes. The concordant high-risk pairs showed volume loss in orbitofrontal subdivisions. High-risk members from the discordant twin pairs exhibited volume reduction in the right inferior dorsolateral prefontal cortex. In addition, the posterior corpus callosum was compromised in concordant high-risk pairs, only. Our findings indicate that inattention and hyperactivity symptoms are associated with anatomical abnormalities of a distributed action-attentional network. Different brain areas of this network appear to be affected in inattention/hyperactivity caused by genetic (i.e., high concordant MZ pairs) vs. environmental (i.e., high-low discordant MZ pairs) risk factors. These results provide clues that further our understanding of brain alterations in ADHD.

Colonic bacterial activity determines the symptoms in people with fructose-malabsorption.

BACKGROUND/AIM: This study was performed to find a parameter to discriminate symptomatic from asymptomatic subjects with fructose-malabsorption. PATIENTS AND METHODS: Thirty-four subjects (12 m, 22 f; average age, 28.6 years; range 16-60) were investigated after an overnight fast. After intake of 25 g fructose, H2-tests were carried out. Endexspiratory breath samples were taken before the ingestion of the tested sugar and at 30 minute intervals over a 2 hour period. Hydrogen determination was performed immediately after sampling. Results were considered pathological if there was a rise in hydrogen over 20 ppm and a twofold increase from the initial value. Aerobic and anaerobic cultures from stool bacteria were set and incubated with 0.5 g fructose. RESULTS: Among 34 healthy controls, 13 malabsorbers (38%) were detected. Out of these malabsorbers, 6 (46%) reported gastrointestinal concomitant symptoms. Symptomatic and asymptomatic subjects with fructose-malabsorption showed a comparable increase in hydrogen levels. The disappearance rate of fructose in the stool cultures was significantly elevated in the symptomatic group compared with the asymptomatic, but only in the anaerobic culture. CONCLUSION: This activity of colonic bacteria, significantly discriminating symptomatic subjects with fructose-malabsorption from asymptomatic, enhances the importance of fructose-malabsorption in the differential diagnosis of people with non-specific abdominal complaints. Antibiotic therapy in severe cases should be considered a therapeutical approach. Moreover these results may support the role of nutritional carbohydrates in the pathogenesis of colonic diseases.

Definition of a new intralaboratory limit value for a positive UDS assay in vitro.

In our laboratory, we routinely perform the unscheduled DNA synthesis (UDS) assay in vitro using rat primary liver cells and autoradiographical evaluation. The fixed limit of +5 nuclear net grains (NNG) for a positive UDS response no longer seems to be appropriate because of the advanced techniques that are now used. Considering our historical data (mean vehicle control NNG of 45 experiments = -1.5; highest observed mean NNG value in 126 control slides = +1.63 NNG) we will use a mean value of +2 NNG as our new intralaboratory limit value for a positive UDS assay, independent of the statistical evaluation. Experiments with a mean NNG count in the vehicle control of > +0.5 will be rejected as invalid and repeated since mean values of > +0.23 NNG were never reached. Additionally, the NNG data obtained will be subjected to a newly proposed statistical method which includes both the actual and the mean historical control NNG value. First, the sum of the actual and the mean historical control value is divided by two. Secondly, the calculated control value is pairwise compared with the treated groups by the one-sided Dunnett's test. This might be a helpful tool to evaluate a weak or equivocal UDS response.

Physical state and biological activity of human papillomavirus genomes in precancerous lesions of the female genital tract.

The DNA of distinct human papillomaviruses (HPVs) is regularly detected in the majority of human cervical carcinomas. In contrast to benign HPV-induced genital lesions, where the viral genomes are exclusively present as episomes, in cervical carcinomas HPV type 16 (HPV16) DNA was found to be integrated into the host DNA. In order to determine the physical state and expression of HPV DNA sequences at different stages of tumour development, we analysed a series of cervical lesions (mild, moderate and severe dysplasia and carcinoma in situ) that are considered precursors of carcinomas of the cervix. In 66.6% (18 of 27) of the tumours, HPV16 DNA was present. While in mild dysplasias only episomal HPV genomes were found, in all higher grade lesions integration of the viral DNA was detected. There was a close correlation between the episomal state and the expression of the HPV16 genomes: in 15 cases harbouring episomal HPV16 DNA (seven of which also contained integrated genomes) viral transcripts were present. We conclude that integration of HPV genomes takes place very early in cervical cancer development. In addition, the episomal state of the viral DNA depends on viral gene expression. The same conclusion, however, is not applicable in those lesions (three severe dysplasias) containing exclusively integrated HPV16 DNA. Thus, HPV16 DNA can persist in an integrated state without recognizable transcriptional activity. These results point to HPV16 as one potential prerequisite for the first steps in the multistage development of human cervical cancer.

Human papillomavirus DNA replication mediated by simian virus 40 T antigen in trans.

The putative E1 gene product of papillomaviruses is thought to be involved in the initiation of viral replication, as large-T antigen (T antigen) is in the case of polyomaviruses. Mouse cell lines cloned after transformation by a plasmid consisting of the simian virus 40 (SV40) early region and the complete genome of human papillomavirus type 16 (HPV16) maintained episomal plasmid DNA. In contrast, the DNAs of either SV40 or HPV16, when employed separately in transfection experiments, were consistently integrated into the host DNA. To test the hypothesis that SV40 T antigen might be involved in the replication of the hybrid plasmids, HPV16 DNA was used in a transient replication assay for transfection of either CV-1 or COS-7 cells. The HPV16 DNA replicated to a high copy number in the T antigen-producing COS-7 cells, but failed to replicate in the CV-1 cells. To define the HPV16 sequences that were essential for the plasmid maintenance in SV40 T antigen-producing cells, restriction fragments of HPV16 were analysed for their replication capacity in COS-7 cells. Here it is reported that the presence of the coding region of the putative E1 gene product of HPV16 together with the 5' transcriptional control elements is essential and is sufficient to support plasmid replication mediated by SV40 T antigen in trans.

Cloning and characterization of budgerigar fledgling disease virus, an avian polyomavirus.

The DNA of a virus isolated from fledgling budgerigars, designated BFDV, was cloned and analyzed with regard to its relationship to the polyomavirus subgroup of the papovavirus family. Under relaxed conditions, the DNA of BFDV cross-hybridized with the DNAs of members of the polyomavirus subgroup, such as the mouse polyomavirus, the monkey viruses simian virus 40, stump-tailed macaque virus, and lymphotropic papovavirus, and the human viruses JCV and BKV. Under stringent conditions, however, no homologies could be detected. Furthermore, BFDV propagated in chicken embryo cells was antigenically related to the capsid antigen(s) of the other polyomaviruses. The virus was able to transform hamster embryo cells in vitro which is a typical feature of polyomaviruses. These data clearly indicate that BFDV is a new distinct member of the polyomavirus genus representing the first nonmammalian polyomavirus.

Papillomavirus genomes in human cervical tumors: analysis of their transcriptional activity.

Four of six human cervical carcinoma biopsies were shown to contain the DNA of the human papillomavirus type 16 (HPV-16) covalently linked with the tumor cell DNA. HPV-16-specific mRNA species were observed in only one of the four tumors. No such sequences were found in the three other specimens in conditions that permitted the detection of less than one mRNA molecule per cell. It is concluded that maintenance of the malignant nature of these cervical tumors does not depend on the continuous transcriptional activity of HPV-16.

[Merkeloma (Merkel cell carcinoma) from the clinical viewpoint based on 4 cases]. / Das Merkeliom (Merkelzellkarzinom) aus klinischer Sicht anhand von 4 Fällen.

We report on 4 patients suffering from Merkel Cell Carcinoma. Although we have to deal with a lot of difficulties concerning the differentiation of macroscopically as well as microscopically similar tumors, there is a way to diagnosis by means of histology and neurone-specific enolase.

Transcription of episomal papillomavirus DNA in human condylomata acuminata and Buschke-Löwenstein tumours.

Condylomata acuminata and Buschke-Löwenstein tumours were analysed for the presence of human papillomavirus (HPV) transcripts. HPV DNA and RNA sequences were present in all 13 samples investigated. Ten contained HPV6 and three harboured HPV11. The HPV genomes were found exclusively as extrachromosomal circular molecules. In six biopsy specimens, viral RNA transcripts were not detectable by Northern blot analysis but could be demonstrated in dot blots. From seven HPV6-containing samples it was possible to obtain sufficient amounts of undegraded mRNA. We have found consistently one major species (1.4 kb). Less prominent species of 1.7, 1.85, 2.7 and 3.2 kb, respectively, were also detected. The 3' ends of the HPV6 mRNAs were located between nucleotides 3917 and 4441 in the putative early region and between nucleotides 7232 and 7696 in the putative late region. The arrangement of the 3' termini and the adjacent coding areas within the HPV6 genome show that the RNA species are transcribed from one DNA strand.

The physical state of hybrid genomes containing simian virus 40 and bovine papilloma virus DNA sequences in transformed clonal cell lines.

To test whether the covalent linkage of simian virus 40 (SV40) A gene DNA sequences might lead to integration of bovine papilloma virus type 1 (BPV-1) DNA sequences, recombinant pBR322 plasmids containing both the transforming region of the BPV-1 genome and the SV40 A gene were used for transformation of rodent cells. Plasmids containing both regions transformed with higher efficiency than plasmids containing either region alone. Various clonal cell lines were established and examined with regard to the physical state and the expression of the viral DNA sequences. BPV-1 RNA sequences were detected and the SV40 T-antigen was expressed. The plasmid sequences persisted in all cases in an unintegrated state. In no case was it possible to find evidence for integration of BPV-1 sequences.

[Effect of 8-methoxypsoralen and blacklight on microorganisms in vitro and in experimental trichophytosis in guinea pigs]. / Zur Wirkung von 8-Methoxypsoralen (8-MOP) und Blacklight auf Mikroorganismen in vitro und den Ablauf der experimentellen Meerschweinchen-Trichophytie

The lack of experimental test models causes problems in comparative evaluation of photodynamic effects of 8-MOP and its possible derivatives after irradiation with blacklight or other irradiation sources. In our experiments in vitro, tests with various microorganisms and the in vivo model of experimental dermatophytosis in guinea pigs by Trichophyton mentagrophytes appeared to be suitable. In vivo, 8-MOP was applicated orally and topically in two formulations.