Recent evidence indicated that the ZNF804A (rs1344706) risk allele A is associated with better co... more Recent evidence indicated that the ZNF804A (rs1344706) risk allele A is associated with better cognitive performance in patients with schizophrenia. Moreover, it has been demonstrated that ZNF804A may also be related to relatively intact gray matter volume in patients. To further explore these putatively protective effects, the impact of ZNF804A on cortical thickness and folding was examined in this study. To elucidate potential molecular mechanisms, an allelic-specific gene expression study was also carried out. Magnetic resonance imaging cortical thickness and folding were computed in 55 genotyped patients with schizophrenia and 40 healthy controls. Homozygous risk allele carriers (AA) were compared with AC/CC carriers. ZNF804A gene expression was analyzed in a prefrontal region using postmortem tissue from another cohort of 35 patients. In patients, AA carriers exhibited significantly thicker cortex in prefrontal and temporal regions and less disturbed superior temporal cortical folding, whereas the opposite effect was observed in controls, ie, AA carrier status was associated with thinner cortex and more severe altered cortical folding. Along with this, our expression analysis revealed that the risk allele is associated with lower prefrontal ZNF804A expression in patients, whereas the opposite effect in controls has been observed by prior analyses. In conclusion, our analyses provide convergent support for the hypothesis that the schizophrenia-associated ZNF804A variant mediates protective effects on cortex structure in patients. In particular, the allele-specific expression profile in patients might constitute a molecular mechanism for the observed protective influence of ZNF804A on cortical thickness and folding and potentially other intermediate phenotypes.
The synthesis of the ganglioside LM1 (1) has been performed by glycosidation of 2 with azidosphin... more The synthesis of the ganglioside LM1 (1) has been performed by glycosidation of 2 with azidosphingosine 3, followed by reduction of the azido group, acylation with stearine anhydride (4), and solvolysis. 2 was obtained from sialyl xanthate 5 and tetrasaccharide 6 in the presence of phenylsulfenyl triflate. The tetrasaccharide acceptor 6 was prepared from the lactose derivatives 7 and 8.
Suramin, an inhibitor of viral reverse transcriptase, has been used fn the therapy of trypanosomi... more Suramin, an inhibitor of viral reverse transcriptase, has been used fn the therapy of trypanosomiasis and onchocerciasis since 1920 and 1947, respectively. More recently, suramin has been suggested for the treatment of the acquired immuno-deficiency syndrom (AIDS). Plasma suramin levels have been determined colorimetrically after hydrolysis [1, 2]. Recently, a very effective extraction procedure for suramin from plasma has been reported [3]. Following extraction suramin was quantitated by reverse phase ion-pairing HPLC using a gradient elution system. This method requires exact timing and equilibration delays. Here we report a simplification of the procedure which allows very rapid determination of suramin by an isocratic elution system.
Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease for which MH suscepti... more Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease for which MH susceptibility (MHS) is transmitted as an autosomal dominant trait. A potentially life-threatening MH crisis is triggered by exposure to commonly used inhalational anesthetics and depolarizing muscle relaxants. The first malignant hyperthermia susceptibility locus (MHS1) was identified on human chromosome 19q13.1, and evidence has been obtained that defects in the gene for the calcium-release channel of skeletal muscle sarcoplasmic reticulum (ryanodine receptor; RYR1) can cause some forms of MH. However, MH has been shown to be genetically heterogeneous, and additional loci on chromosomes 17q and 7q have been suggested. In a collaborative search of the human genome with polymorphic microsatellite markers, we now found linkage of the MHS phenotype, as assessed by the European in vitro contracture test protocol, to markers defining a 1-cM interval on chromosome 3q13.1. A maximum multipoint lod sco...
Astrocytomas are intracranial malignancies for which invasive growth and high motility of tumour ... more Astrocytomas are intracranial malignancies for which invasive growth and high motility of tumour cells preclude total resection; the tumours usually recur in a more aggressive and, eventually, lethal form. Clinical outcome is highly variable and the accuracy of morphology-based prognostic statements is limited. In order to identify novel molecular markers for prognosis we obtained expression profiles of: i) tumours associated with particularly long recurrence-free intervals, ii) tumours which led to rapid patient death, and iii) tumour-free control brain. Unsupervised data analysis completely separated the three sample entities indicating a strong impact of the selection criteria on general gene expression. Consequently, significant numbers of specifically expressed genes could be identified for each entity. An extended set of tumours was then investigated by RT-PCR targeting 12 selected genes. Data from these experiments were summarised into a sample-specific index which assigns tu...
Summary: A simple, sensitive and precise isocratic HPLC method for the determination of total hom... more Summary: A simple, sensitive and precise isocratic HPLC method for the determination of total homocysteine in human plasma is described. The thiol compounds were liberated from plasma proteins by reduction with tn-n-butylphosphine and derivatized with a thiol-specific fluorogenic marker, 7-fluoro-benzo-2-oxa-l,3-diazole-4-sulpho-nate. The derivatives were separated isocratically within 7 min by reversed-phase HPLC using a Superspher 100 RP-18 column as stationary phase. By using this approach more than 200 samples a day can be assayed for total homocysteine. The method was linear up to 100 μιηοΐ/ΐ and proved to be sensitive with a detection limit of 0.1 μηιοΐ/ΐ and the lowest limit of reliable quantification of 0.5 umol/1 for homocysteine in buffer. Intra- and inter-assay coefficients of variation were both <4 % at a concentration of 10 umol/1 homocysteine. Similar results were obtained for homocysteine concentrations between 0.5 and 100 μηιοΐ/ΐ. The analytical recovery for these...
Large deletions that are associated with insertions of Alu-derived sequence represent a rare, but... more Large deletions that are associated with insertions of Alu-derived sequence represent a rare, but potentially unique class of alterations. Whether they form by a one-step mechanism or by a primary insertion step followed by an independent secondary deletion step is not clear. We resolved two disease-associated SPAST deletions, which involve distinct exons by long range PCR. Alu-derived sequence was observed between the breakpoints in both cases. The intronic regions that represent the targets of potentially involved Alu retrotransposition events overlapped. Microsatellite-and SNP-based haplotyping indicated that both deletions originated on one and the same founder allele. Our data suggest that the deletions are best explained by two-step insertion-deletion scenarios for which a single Alu retrotransposition event represents the shared primary step. This Alu then mediated one of the deletions by non-homologous end joining and the other by non-allelic homologous recombination. Our findings thus strongly argue for temporal separation of insertion and deletion in Alu insertion-associated deletions. They also suggest that certain Alu integrations confer a general increase in local genomic instability, and that this explains why they are usually not detected during the probably short time that precedes the rearrangements they mediate.
A yeast artificial chromosome (YAC) contig was constructed encompassing the entire region on chro... more A yeast artificial chromosome (YAC) contig was constructed encompassing the entire region on chromosome 17p13 where the autosomal recessive disorder infantile nephropathic cystinosis (MIM 21980, CTNS-LSB) has been genetically mapped. It comprises seven clones ordered by their content of a series of six sequence-tagged sites (STSs). Fluorescence in situ hybridisation (FISH) revealed two chimaeric clones. The order of four polymorphic STSs mapped with the contig was consistent with that of the known genetic map with the exception of markers D17S1583 (AFMb307zg5) and D17S1798 (AFMa202xf5) where a telomeric location of D17S1583 was inferred from the contig; two non-polymorphic STSs were localised within the marker frame-work. From the analysis of recombination events in an unaffected individual as defined by leucocyte cystine levels we support the high-resolution mapping of this region to a small genetic interval and show that it is entirely represented on a single, non-chimaeric YAC cl...
to 4 ng/ mL. At the initial period (2000-2003), 12 biopsy cores were performed (nϭ220; group 1) a... more to 4 ng/ mL. At the initial period (2000-2003), 12 biopsy cores were performed (nϭ220; group 1) and since 2004, we have adopted a 22-core procedure as an initial strategy (nϭ314; group 2). Up to 34 prostate cores were taken for repeated biopsy. Data of both groups were compared to assess the prostate detection rate and the interest of extended biopsy cores (Ն 24) for repeated biopsy was evaluated. Results: Both groups were comparable regarding age, clinical stage, PSA levels and complications rate. Cancer detection rates for the 12 systematic biopsy schemes vs. the 22 biopsy cores protocol were 44.1% (97/220) vs. 53.2% (167/314) when all the patients were considered (pϭ0.04). When considering only the clinical stage T1, the difference between the 2 groups was more pronounced (31.4% vs. 44.1%; pϭ0.02). When repeating the biopsy, a scheme of 24 to 30 cores led to a higher detection of prostate cancer with fewer than 24 cores (69.2% vs. 32.8%; pϭ0.01) but increasing the cores above 30 proved unnecessary. Conclusion: Our data support the interest of the saturation technique using 22 cores for prostate cancer detection as an initial strategy. A greater number of cores, but fewer than 30 can be beneficial when repeating the prostate biopsy. Nevertheless, the cost and work overruns for the pathologist in that type of procedure should be taken into account.
Malignant hyperthermia is an inherited autosomal disorder of skeletal muscle in which certain vol... more Malignant hyperthermia is an inherited autosomal disorder of skeletal muscle in which certain volatile anesthetics and depolarizing muscle relaxants trigger an abnormally high release of Ca 2+ from the intracellular Ca 2+ store, the sarcoplasmic reticulum. In about 50% of ...
Recent evidence indicated that the ZNF804A (rs1344706) risk allele A is associated with better co... more Recent evidence indicated that the ZNF804A (rs1344706) risk allele A is associated with better cognitive performance in patients with schizophrenia. Moreover, it has been demonstrated that ZNF804A may also be related to relatively intact gray matter volume in patients. To further explore these putatively protective effects, the impact of ZNF804A on cortical thickness and folding was examined in this study. To elucidate potential molecular mechanisms, an allelic-specific gene expression study was also carried out. Magnetic resonance imaging cortical thickness and folding were computed in 55 genotyped patients with schizophrenia and 40 healthy controls. Homozygous risk allele carriers (AA) were compared with AC/CC carriers. ZNF804A gene expression was analyzed in a prefrontal region using postmortem tissue from another cohort of 35 patients. In patients, AA carriers exhibited significantly thicker cortex in prefrontal and temporal regions and less disturbed superior temporal cortical folding, whereas the opposite effect was observed in controls, ie, AA carrier status was associated with thinner cortex and more severe altered cortical folding. Along with this, our expression analysis revealed that the risk allele is associated with lower prefrontal ZNF804A expression in patients, whereas the opposite effect in controls has been observed by prior analyses. In conclusion, our analyses provide convergent support for the hypothesis that the schizophrenia-associated ZNF804A variant mediates protective effects on cortex structure in patients. In particular, the allele-specific expression profile in patients might constitute a molecular mechanism for the observed protective influence of ZNF804A on cortical thickness and folding and potentially other intermediate phenotypes.
The synthesis of the ganglioside LM1 (1) has been performed by glycosidation of 2 with azidosphin... more The synthesis of the ganglioside LM1 (1) has been performed by glycosidation of 2 with azidosphingosine 3, followed by reduction of the azido group, acylation with stearine anhydride (4), and solvolysis. 2 was obtained from sialyl xanthate 5 and tetrasaccharide 6 in the presence of phenylsulfenyl triflate. The tetrasaccharide acceptor 6 was prepared from the lactose derivatives 7 and 8.
Suramin, an inhibitor of viral reverse transcriptase, has been used fn the therapy of trypanosomi... more Suramin, an inhibitor of viral reverse transcriptase, has been used fn the therapy of trypanosomiasis and onchocerciasis since 1920 and 1947, respectively. More recently, suramin has been suggested for the treatment of the acquired immuno-deficiency syndrom (AIDS). Plasma suramin levels have been determined colorimetrically after hydrolysis [1, 2]. Recently, a very effective extraction procedure for suramin from plasma has been reported [3]. Following extraction suramin was quantitated by reverse phase ion-pairing HPLC using a gradient elution system. This method requires exact timing and equilibration delays. Here we report a simplification of the procedure which allows very rapid determination of suramin by an isocratic elution system.
Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease for which MH suscepti... more Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease for which MH susceptibility (MHS) is transmitted as an autosomal dominant trait. A potentially life-threatening MH crisis is triggered by exposure to commonly used inhalational anesthetics and depolarizing muscle relaxants. The first malignant hyperthermia susceptibility locus (MHS1) was identified on human chromosome 19q13.1, and evidence has been obtained that defects in the gene for the calcium-release channel of skeletal muscle sarcoplasmic reticulum (ryanodine receptor; RYR1) can cause some forms of MH. However, MH has been shown to be genetically heterogeneous, and additional loci on chromosomes 17q and 7q have been suggested. In a collaborative search of the human genome with polymorphic microsatellite markers, we now found linkage of the MHS phenotype, as assessed by the European in vitro contracture test protocol, to markers defining a 1-cM interval on chromosome 3q13.1. A maximum multipoint lod sco...
Astrocytomas are intracranial malignancies for which invasive growth and high motility of tumour ... more Astrocytomas are intracranial malignancies for which invasive growth and high motility of tumour cells preclude total resection; the tumours usually recur in a more aggressive and, eventually, lethal form. Clinical outcome is highly variable and the accuracy of morphology-based prognostic statements is limited. In order to identify novel molecular markers for prognosis we obtained expression profiles of: i) tumours associated with particularly long recurrence-free intervals, ii) tumours which led to rapid patient death, and iii) tumour-free control brain. Unsupervised data analysis completely separated the three sample entities indicating a strong impact of the selection criteria on general gene expression. Consequently, significant numbers of specifically expressed genes could be identified for each entity. An extended set of tumours was then investigated by RT-PCR targeting 12 selected genes. Data from these experiments were summarised into a sample-specific index which assigns tu...
Summary: A simple, sensitive and precise isocratic HPLC method for the determination of total hom... more Summary: A simple, sensitive and precise isocratic HPLC method for the determination of total homocysteine in human plasma is described. The thiol compounds were liberated from plasma proteins by reduction with tn-n-butylphosphine and derivatized with a thiol-specific fluorogenic marker, 7-fluoro-benzo-2-oxa-l,3-diazole-4-sulpho-nate. The derivatives were separated isocratically within 7 min by reversed-phase HPLC using a Superspher 100 RP-18 column as stationary phase. By using this approach more than 200 samples a day can be assayed for total homocysteine. The method was linear up to 100 μιηοΐ/ΐ and proved to be sensitive with a detection limit of 0.1 μηιοΐ/ΐ and the lowest limit of reliable quantification of 0.5 umol/1 for homocysteine in buffer. Intra- and inter-assay coefficients of variation were both <4 % at a concentration of 10 umol/1 homocysteine. Similar results were obtained for homocysteine concentrations between 0.5 and 100 μηιοΐ/ΐ. The analytical recovery for these...
Large deletions that are associated with insertions of Alu-derived sequence represent a rare, but... more Large deletions that are associated with insertions of Alu-derived sequence represent a rare, but potentially unique class of alterations. Whether they form by a one-step mechanism or by a primary insertion step followed by an independent secondary deletion step is not clear. We resolved two disease-associated SPAST deletions, which involve distinct exons by long range PCR. Alu-derived sequence was observed between the breakpoints in both cases. The intronic regions that represent the targets of potentially involved Alu retrotransposition events overlapped. Microsatellite-and SNP-based haplotyping indicated that both deletions originated on one and the same founder allele. Our data suggest that the deletions are best explained by two-step insertion-deletion scenarios for which a single Alu retrotransposition event represents the shared primary step. This Alu then mediated one of the deletions by non-homologous end joining and the other by non-allelic homologous recombination. Our findings thus strongly argue for temporal separation of insertion and deletion in Alu insertion-associated deletions. They also suggest that certain Alu integrations confer a general increase in local genomic instability, and that this explains why they are usually not detected during the probably short time that precedes the rearrangements they mediate.
A yeast artificial chromosome (YAC) contig was constructed encompassing the entire region on chro... more A yeast artificial chromosome (YAC) contig was constructed encompassing the entire region on chromosome 17p13 where the autosomal recessive disorder infantile nephropathic cystinosis (MIM 21980, CTNS-LSB) has been genetically mapped. It comprises seven clones ordered by their content of a series of six sequence-tagged sites (STSs). Fluorescence in situ hybridisation (FISH) revealed two chimaeric clones. The order of four polymorphic STSs mapped with the contig was consistent with that of the known genetic map with the exception of markers D17S1583 (AFMb307zg5) and D17S1798 (AFMa202xf5) where a telomeric location of D17S1583 was inferred from the contig; two non-polymorphic STSs were localised within the marker frame-work. From the analysis of recombination events in an unaffected individual as defined by leucocyte cystine levels we support the high-resolution mapping of this region to a small genetic interval and show that it is entirely represented on a single, non-chimaeric YAC cl...
to 4 ng/ mL. At the initial period (2000-2003), 12 biopsy cores were performed (nϭ220; group 1) a... more to 4 ng/ mL. At the initial period (2000-2003), 12 biopsy cores were performed (nϭ220; group 1) and since 2004, we have adopted a 22-core procedure as an initial strategy (nϭ314; group 2). Up to 34 prostate cores were taken for repeated biopsy. Data of both groups were compared to assess the prostate detection rate and the interest of extended biopsy cores (Ն 24) for repeated biopsy was evaluated. Results: Both groups were comparable regarding age, clinical stage, PSA levels and complications rate. Cancer detection rates for the 12 systematic biopsy schemes vs. the 22 biopsy cores protocol were 44.1% (97/220) vs. 53.2% (167/314) when all the patients were considered (pϭ0.04). When considering only the clinical stage T1, the difference between the 2 groups was more pronounced (31.4% vs. 44.1%; pϭ0.02). When repeating the biopsy, a scheme of 24 to 30 cores led to a higher detection of prostate cancer with fewer than 24 cores (69.2% vs. 32.8%; pϭ0.01) but increasing the cores above 30 proved unnecessary. Conclusion: Our data support the interest of the saturation technique using 22 cores for prostate cancer detection as an initial strategy. A greater number of cores, but fewer than 30 can be beneficial when repeating the prostate biopsy. Nevertheless, the cost and work overruns for the pathologist in that type of procedure should be taken into account.
Malignant hyperthermia is an inherited autosomal disorder of skeletal muscle in which certain vol... more Malignant hyperthermia is an inherited autosomal disorder of skeletal muscle in which certain volatile anesthetics and depolarizing muscle relaxants trigger an abnormally high release of Ca 2+ from the intracellular Ca 2+ store, the sarcoplasmic reticulum. In about 50% of ...
Uploads
Papers by Thomas Deufel