Cerebrospinal fluid chimerism analysis in patients with neurological symptoms after allogeneic cell transplantation.

Central nervous system (CNS) complications have been described in patients undergoing allogeneic hematopoietic cell transplantation (alloHCT). Cerebrospinal fluid (CSF) analysis is included in the diagnostic workup in patients with neurological symptoms after alloHCT. CSF donor-recipient chimerism analysis usually is not used to evaluate patients with neurological complications after alloHCT. To assess the potential contribution of CSF donor-recipient chimerism in patients with neurological complications, we analyzed 85 CSF samples from 50 patients with neurological complications after alloHCT. After alloHCT, 21 patients showed the presence of recipient-derived DNA. In 13 of these patients, recurrence of the underlying disease was detected in CSF. There was a moderate correlation between the recipient DNA percentage as detected by short tandem repeat (STR) amplification and the cell concentration in CSF (Spearmann r: 0.66 P=0.004). The percentage of cells with immunophenotypic abnormalities from patients relapsing in the CNS detected by flow cytometry showed a strong correlation with the percentage of recipient-derived DNA in CSF assessed by STR analysis (Spearmann r: 0.83 P=0.0008). Donor-recipient chimerism analysis in CSF in patients with neurological symptoms after alloHCT is a practical, feasible and useful complementary method to the already established methodologies included in the diagnostic workup.

Compensating motion artifacts of 3D in vivo SD-OCT scans.

We propose a probabilistic approach for compensating motion artifacts in 3D in vivo SD-OCT (spectral-domain optical coherence tomography) tomographs. Subject movement causing axial image shifting is a major problem for in vivo imaging. Our technique is applied to analyze the tissue at percutaneous implants recorded with SD-OCT in 3D. The key challenge is to distinguish between motion and the natural 3D spatial structure of the scanned subject. To achieve this, the motion estimation problem is formulated as a conditional random field (CRF). For efficient inference, the CRF is approximated by a Gaussian Markov random field. The method is verified on synthetic datasets and applied on noisy in vivo recordings showing significant reduction of motion artifacts while preserving the tissue geometry.

Novel homozygous mutation (c.175delG) in platelet glycoprotein ITGA2B gene as cause of Glanzmann's thrombasthenia type I.

BACKGROUND: Glanzmann's thrombasthenia (GT), is a rare autosomal recessive bleeding disorder. Platelets from patients with GT show quantitative or qualitative defects of the platelet membrane glycoprotein (GP) IIb/IIIa complex. A variety of genetic defects in ITGA2B and ITGB3 (genes for GPIIb and GPIIIa) has been described causing the clinical entity of GT. PATIENTS: A newborn with bleeding symptoms (petechiae) platelet analyses revealed an inherited primary hemostasis disorder. METHODS/RESULTS: Analyses of patient's platelets using flow cytometry and immunoblotting showed absence of GPIIb protein and reduced amount of GPIIIa. Using restriction fragment length polymorphism heterozygosity for the deletion could be identified in the parents and in two siblings. Expression studies in mammalian cells revealed that the mutant GPIIb is missing and additionally affects the expression of wildtype GPIIIa. This deletion leads to a truncation at the very N-terminal region of the GPIIb protein. CONCLUSION: The present study describes a patient with GT associated with a novel homozygous deletion (c.175delG) in exon 1 of ITGA2B. This deletion led to a reading frameshift and caused a severely truncated form of GPIIb.

Compound heterozygous mutations in 2 siblings with Hermansky-Pudlak syndrome type 1 (HPS1).

BACKGROUND: Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder causing oculocutaneous albinism, bleeding disorder and ceroid lipofuscinosis. Platelets from HPS patients are characterized by the absence of dense (delta)-bodies. There are eight known human HPS GENES (HPS1-HPS8), each leading to a particular clinical HPS subtype. Restrictive lung disease, granulomatous colitis and cardiomyopathy have been described in HPS1 patients. PATIENTS: We identified HPS1 in Russian and in German siblings. All four patients show a typical HPS phenotype. The two older Russian patients demonstrate excessive bleeding after tooth extractions, recurrent epistaxis and hematomas. The two younger German patients suffer only from hematomas, so far. METHODS/RESULTS: Patients' platelets showed severe pathological agglutination/aggregation. Flow cytometry analysis demonstrated absence of platelet delta-granule secretion. Three different mutations in the HPS1 gene were found in the two families. Two mutations, p.H119delC and p.Q397delC identified in the Russian siblings had been previously described. The German siblings presented with a novel frameshift mutation (p.Q32_S33delCAGT) and the known p.Q397delC mutation. CONCLUSION: Patients with oculocutaneous albinism should be investigated for increased clinical bleeding symptoms. In case of increased bleeding symptoms, analyses of primary hemostasis should be initiated to confirm HPS. Molecular genetic investigations should be performed to distinguish the different subtypes of HPS which is important for therapy and prognosis.

Septins, a novel group of GTP-binding proteins: relevance in hemostasis, neuropathology and oncogenesis.

Septins are a novel family of GTP-binding proteins which are essential for cytokinesis, vesicle trafficking, cytoskeletal reorganization and membrane dynamics. They are abundantly expressed in many mitotic cells. Interestingly, they are also expressed in non-dividing cells such as neurons and platelets in which they play an important role in exocytosis. Platelets from SEPT5 knockout mice show an enhanced serotonin secretion and platelet aggregation in response to subthreshold levels of agonists. Septins are associated with a wide array of critical biological events such as neoplasia, neurodegenerative diseases, infections and exocytosis. The role of septins in oncogenesis is complex. Increased expression of some septins seems to trigger the growth of tumor cells. However, other septin isoforms are shown to promote apoptosis and function as tumor suppressor proteins. Interestingly, septins form complexes consisting of multiple septin polypeptides and assemble into filaments and ring-like, higher-order structures. The different septins and their various isoforms seem to determine the function of the septin complex.

A large Swiss family with Bernard-Soulier syndrome - Correlation phenotype and genotype.

Bernard-Soulier syndrome (BSS) is a rare, autosomal recessive inherited bleeding disorder associated with thrombocytopenia, thrombocytopathy and giant platelets. BSS is caused by genetic alterations of the glycoprotein (GP) Ib/V/IX complex. We report on a large Swiss family of whom four family members suffer from BSS. Here, a homozygous missense mutation in position 1829 (A(R)G) of the GPIX gene constituting a N45S substitution is the cause for the bleeding symptoms. A total of 38 family members within two generations were analyzed regarding the N45S mutation by DNA sequencing and restriction fragment length polymorphism. The laboratory parameters which are characteristically for BSS such as platelet count, platelet volume and the expression of CD42a (GPIX), CD42b (GPIbalpha) and CD41 (GPIIb) were measured for all 38 individuals. The four homozygous patients showed bleeding symptoms, thrombocytopenia and giant platelets. In these patients, the expression of CD42a (GPIX), CD42b (GPIbalpha) was diminished. Interestingly, the intensity of the bleeding symptoms of the 4 homozygous family members seemed to vary although they carry the same mutation. The 24 heterozygous carriers did not differ significantly from their 10 wildtype family members regarding bleeding symptoms and laboratory analysis.

Human endothelial cell septins: SEPT11 is an interaction partner of SEPT5.

The septin SEPT11 is a novel member of the highly conserved septin family. Septins are cytoskeletal GTPases, which form heteropolymeric complexes. They are involved in cytokinesis and other cellular processes, such as vesicle trafficking and exocytosis. SEPT11 has strong homology to SEPT8. Previously, we identified the interaction of SEPT5 and SEPT8. Using the yeast two-hybrid system, we now demonstrate that SEPT11 partners with SEPT5. The molecular interaction of SEPT11 with SEPT5 was verified by coprecipitation of SEPT5 and SEPT11 from lysates of the human T-cell leukaemia cell line JURKAT and by fluorescence resonance energy transfer. The interaction between SEPT5 and SEPT11 requires the GTP-binding domain and the C-terminal extension. Western analysis in various mouse and human tissues revealed that expression of SEPT11 is restricted to the same tissues as those expressing SEPT5, suggesting that SEPT11 and SEPT5 are components of a cell-specific septin complex. SEPT5, which is expressed in human umbilical vein endothelial cells (HUVECs), has been reported to play an important role in exocytosis. We now report that HUVECs also express SEPT11. Given the interactivity between SEPT5 and SEPT11 as shown above and their coexpression in HUVECs, it may be that a complex formed by these two proteins is involved in the exocytosis mechanism in HUVECs.

[Cell differentiation of a human bone marrow cell culture under the influence of UHMW-PE debris]. / Zelldifferenzierung einer humanen Knochenmarkzellkultur unter dem Einfluss von UHMW-PE Abriebpartikeln.

AIM: The purpose of the present study was to evaluate the influence of ultra-high-molecular-weight polyethylene (UHMW-PE), which is the major constituent of the material debris formed as a result of orthopaedic implant wear, on the cellular differentiation in a modified in vitro model. METHODS: UHMW-PE particles (Ø < or = 7.5 microm) were suspended in soluble collagen type I and subsequently solidified in different concentrations (10(5), 10(6) and 10(7) particles per well) on the bottom of the wells. Human bone marrow cells in a concentration of 3 x 10(6) cells per well were seeded on the collagen-particle substrate and maintained for up to 72 h. The response of the cells to the particles was examined by light microscopy, scanning electron microscopy and FACS analysis compared to cells on control collagen surfaces without any particles. RESULTS: Light and scanning microscopic evaluation revealed that the UHMW-PE particles, which had built large conglomerates (Ø 7.5 microm), were mainly surrounded by the cells and less phagocytosed. The results of the FACS analysis revealed significant differences in CD3/CD4 positive, CD14 positive and CD19 positive cells (p < 0.05). A significant elevation of CD3/CD4 positive and CD14 positive cells (p < 0.05) was observed after the period of culture (72 h) whereas a significant decrease could be detected in the case of CD19 positive cells. CONCLUSION: The results demonstrate that the particle-induced response by UHMW-PE limits itself not only to the particle macrophage contact but influences also the differentiation of the bone marrow. Moreover, the results confirm that the present method is useful to evaluate the in vitro effects of UHMW-PE wear particles with direct particle cell contact. Although the particles built large conglomerates, it could be shown that a change of the immune-competent cells also occurred.

[Cytokine profile of a human bone marrow cell culture under the influence of UHMW-PE wear particles]. / Zytokinprofil einer humanen Knochenmarkzellkultur unter dem Einfluss von UHMW-PE Abriebpartikeln.

There is considerable evidence that orthopaedic wear debris plays a crucial role in the pathology of aseptic loosening of joint prostheses. The purpose of the present study was to evaluate the influence of ultra-high-molecular-weight polyethylene (UHMW-PE) on the cytokine response in a modified in vitro model. UHMW-PE particles (psi < 7.5 microm) were suspended in soluble collagen type I and subsequently solidified in different concentrations (105,106 and 107 particles per well) on the bottom of the wells. Human bone marrow cells in a concentration of 3 x 106 cells per well were seeded on the collagen-particle substrata and maintained for up to 12 days. The cytokine response (IL-1_, IL-6 and TNF-_) of the cells to the particles were examined by ELISA compared to cells on control collagen surfaces without any particles. Assays for viability using LDH activity were done immediately. Light and scanning microscopic evaluation revealed that the UHMWPE particles, which have built large conglomerates (psi7.5_m), were mainly surrounded by the cells and less phagocytosed. The results of the cytokine release revealed significant differences in interleukin (IL)6, tumor necrosis factor (TNF)- _ and IL-1beta. The cell viability was not affected by the UHMW-PE particles. The results demonstrate that the particle induced cytokine response by UHMW-PE is mainly by the release of Interleukin 6 and TNF- _. Moreover the results confirm that the present method is useful to evaluate the in vitro effects of UHMW-PE wear particles with direct particle cell contact.

Activation of propane 2-nitronate to a genotoxicant in V79-derived cell lines engineered for the expression of rat hepatic sulfotransferases.

2-Nitropropane (2-NP) is a genotoxic hepatocarcinogen in rats. The genotoxicity of the compound has been attributed to a sulfotransferase-mediated formation of DNA-reactive species from the anionic form of 2-NP, propane 2-nitronate (P2N). Several observations have suggested that sulfotransferases (SULTs) 1A1 and/or 1C1 may be important in the activation of P2N to a genotoxicant in rat liver, but a definite proof is lacking. In order to identify the sulfotransferase(s) of rat liver that are capable of activating P2N, we have investigated the genotoxicity of P2N in various V79-derived cell lines engineered for expression of individual forms of rat hepatic sulfotransferases. Genotoxicity was assessed by measuring the induction of DNA repair synthesis. 1-Hydroxymethylpyrene (HMP), which is metabolically activated by most sulfotransferases, served as a positive control. Neither P2N nor HMP induced DNA repair in the parental V79-MZ cells, which do not show any sulfotransferase activity. P2N was also inactive in V79-rHSTa and V79-rHST20 cells, which express specific hydroxysteroid sulfotransferases. By contrast, a clear and concentration-dependent induction of repair synthesis by P2N was observed in V79-rPST-IV and V79-rST1C1 cells, which express rat SULT1A1 and SULT1C1, respectively. HMP was genotoxic in all sulfotransferase-expressing cell lines. Acetone oxime (AO), the tautomeric form of the first reduction product of 2-NP, 2-nitrosopropane, was inactive in all cell lines. The results corroborate the essential role of sulfotransferases in the metabolic activation of P2N to genotoxic products and identify two rat sulfotransferases which are capable of catalyzing the activation step.

Sulfotransferase-mediated activation of mutagens studied using heterologous expression systems.

Sulfation is a common final step in the biotransformation of xenobiotics and is traditionally associated with inactivation. However, the sulfate group is electron-withdrawing and may be cleaved off heterolytically in some molecules leading to electrophilic cations which may form adducts with DNA and other important cellular structures. Since endogenous sulfotransferases do not appear to be expressed in indicator cells of standard mutagenicity tests, rat and human sulfotransferases have been stably expressed in his- Salmonella typhimurium strain TA1538 and Chinese hamster V79 cells. Using these recombinant indicator cells, sulfotransferase-dependent genotoxic activities were detected with N-hydroxy-2-acetylaminofluorene, 2-acetylaminofluorene (in the presence of co-expressed rat cytochrome P450 1A2), hycanthone, 1'-hydroxysafrole, alpha-hydroxytamoxifen and various benzylic alcohols derived from polycyclic aromatic hydrocarbons. In several cases, it was critical that the reactive sulfuric acid conjugates were formed directly within the indicator cells, owing to the inefficient penetration of cell membranes. In other cases, spontaneous benzylic substitution reactions with medium components, such as halogenide ions or amino acids, led to secondary, membrane-penetrating reactive species. Different sulfotransferases, including related forms from rat and human, substantially differed in their substrate specificity towards the investigated promutagens. It is known that some sulfotransferases are expressed with high tissue and cell type specificities. This site-dependent expression together with the limitations in the distribution of reactive sulfuric acid conjugates may explain organotropic effects of compounds activated by this metabolic pathway.

Expression of human estrogen sulfotransferase in Salmonella typhimurium: differences between hHST and hEST in the enantioselective activation of 1-hydroxyethylpyrene to a mutagen.

Various human sulfotransferases (hP-PST, hM-PST, hHST) and rat sulfotransferases (rPST-IV, rHSTa) have already been expressed in Ames' Salmonella strains (in particular in TA1538). Now a further strain, TA1538-hEST, which expresses the human estrogen sulfotransferase (hEST), has been constructed. This strain activated the primary benzylic alcohol 1-hydroxymethylpyrene (1-HMP) and the secondary benzylic alcohol 1-hydroxyethylpyrene (1-HEP) to mutagens. Human sulfotransferases hEST and hHST both activated 1-HEP, but they differed substantially in their enantioselectivity for this compound.

Characterization of thyroid hormone sulfotransferases.

Sulfation is an intriguing pathway of thyroid hormone metabolism since it facilitates the degradation of the hormone by the type I deiodinase (D1). This study reports the preliminary characterization of iodothyronine sulfotransferase activities of rat and human liver cytosol and recombinant rSULT1C1 and hSULT1A1 isoenzymes. All these enzyme preparations catalyzed the sulfation of--in decreasing order of efficiency--3,3'-diiodothyronine (3,3'-T2) > 3,3',5-triiodothyronine (T3) approximately 3,3',5'-triiodothyronine (rT3) > thyroxine (T4). 3,3'-T2 sulfotransferase activity was found to be higher in male than in female rat liver, which has also been shown by others for the expression of rSULT1A1 and rSULT1C1. No sulfation of iodothyronines was observed with rSULT1A1. Different phenol derivatives were found to be potent inhibitors of the sulfation of 3,3'-T2 by native and recombinant sulfotransferases, with pentachlorophenol and 2,4,6-tribromophenol being the most potent. The inhibitions exerted by the different phenols on 3,3'-T2 sulfation by rSULT1C1 correlated better with the effects observed in male than with those in female liver. A strong correlation was also observed between the inhibition profiles of human liver cytosol and hSUL1T1A1. These results suggest that: (1) rSULT1C1 is an important isoenzyme for the sulfation of thyroid hormone in male rat liver; (2) another isoenzyme with similar properties, perhaps rSULT1B1, is responsible for thyroid hormone sulfation in female rat liver and may also contribute to this process in male rat liver; and (3) hSULT1A1 is an important isoenzyme for thyroid hormone sulfation in human liver.

Salmonella strains and mammalian cells genetically engineered for expression of sulfotransferases.

Rat and human sulfotransferases (STs) were expressed in his- S. typhimurium strains. These new bacterial strains detected various mutagens which are difficult to recognize in traditional test systems, including benzylic alcohols derived from polycyclic aromatic hydrocarbons, hycanthone and 1'-hydroxysafrole. STs were also stably expressed in V79 Chinese hamster cells, which do not express endogenous ST and are suitable for the detection of genotoxic effects. Positive responses in these test systems were observed with various benzylic alcohols, including benzo[a]pyrene-7,8,9,10-tetrols. We demonstrate that a few reactive sulfuric acid conjugates are efficiently detected as genotoxicants only when generated directly within the indicator cell.

Stable heterologous expression of hydroxysteroid sulphotransferase in Chinese hamster V79 cells and their use for toxicological investigations.

Various benzylic alcohols are metabolically activated to electrophilic, potentially mutagenic and carcinogenic sulphuric acid esters. The involved sulphotransferases are not expressed in the cell lines in culture which are commonly used for mutagenicity testing. The liver of adult female rats is very efficient in the bioactivation of 1-hydroxymethylpyrene. The major enzyme involved was purified and identified as hydroxysteroid sulphotransferase a. Its cDNA was stably expressed in Chinese hamster V79 cells, which are particularly suited for the quantitative detection of various types of mutations and other genotoxic and cytotoxic effects. The mRNA, protein and enzyme activity levels in the constructed cell lines (V79rSTa-1 and V79rSTa-2) were measured, and the cells were also used in mutagenicity and cytotoxicity investigations with benzylic alcohols. 1-Hydroxymethylpyrene, 9-hydroxymethylanthracene and 6-hydroxymethylbenzo[a]pyrene showed enhanced cytotoxicity in V79rSTa-1 and V79rSTa-2 cells, as compared with sulphotransferase-deficient control cells. In addition, 1-hydroxymethylpyrene induced sister chromatid exchanges, and 6-hydroxymethylbenzo[a]pyrene induced gene mutations in V79rSTa-1 cells. We intend carrying out more investigations with other chemicals on these cell lines. Their advantages, as compared with systems with external metabolising systems, include the formation of the active metabolites within the target cell, as in ST-proficient cells in vivo, eliminating the problems which may result from restricted intercellular transport of reactive and ionized sulphuric acid conjugates. Furthermore, cells expressing other sulphotransferases, including human enzymes, may be constructed and used for comparative investigations.

An undecamer DNA sequence directs termination of human ribosomal gene transcription.

Previously we have shown that a repetitive 18 bp sequence motif, the Sal box (AGGTCGACCAGA/TT/ANTCCG), present in the 3' terminal spacer of mouse rDNA constitutes a termination signal for RNA polymerase I (pol I). Similar sequence elements which are functionally analogous to the murine terminator are present in the spacer of human rDNA. However, the human termination signal is shorter encompassing only 11 bp (GGGTCGACCAG) which correspond to the proximal part of the mouse sequence. Two out of the five human Sal box elements are functionally inactive due to natural point mutations which damage factor binding. A similar sequence motif with a 10 of 11 base identity with the downstream terminators is located upstream of the human transcription initiation site. The upstream element interacts with the same factor(s) as the downstream terminators and is also capable to stop elongating human RNA polymerase I. Despite the human and mouse factors exert different electrophoretic mobilities in gel retardation assays, UV-crosslinking and proteolytic clipping experiments indicate that both the sizes and the tertiary structure of the Sal box binding proteins of both species are very similar. When bound to DNA, both the human and the mouse factor terminate transcription of pol I from the heterologous species. The results implicate that changes in signal sequences necessary for termination have been accompanied by compensatory changes in the DNA binding domain of the protein(s) interacting with the termination signal. In contrast, the protein-protein interactions between the termination factor and the transcribing RNA polymerase I appear to have been conserved during evolution.

Specific interaction of the murine transcription termination factor TTF I with class-I RNA polymerases.

The 18-base-pair sequence element AGGTCGACCAGTACTCCG (the Sal box) signals termination of mouse ribosomal gene transcription. This sequence is recognized by a sequence-specific DNA-binding protein, TTF I, which mediates the termination of transcription by RNA polymerase I (pol I). Subsequently, the ends of the primary transcripts are trimmed by 10 nucleotides in a sequence-dependent 3'-terminal processing reaction. We have now investigated whether TTF I bound to its target sequence will block elongation by any RNA polymerase by steric hindrance, or whether it is specific for elongation by pol I. The results demonstrate that TTF I directs transcription termination with RNA polymerase I from species as divergent as mouse and yeast, but fails to affect elongation by heterologous polymerases (eukaryotic RNA polymerases II and III, Escherichia coli or bacteriophage T3 RNA polymerase). By contrast, purified lac repressor bound to its operator sequence stops elongation by both RNA polymerase I and II.

Purification and characterization of TTFI, a factor that mediates termination of mouse ribosomal DNA transcription.

Termination of rRNA gene transcription is dependent on an 18-base-pair sequence motif, AGGTCGAC CAG AT TA NTCCG (the Sal box), which is present several times in the spacer region downstream of the 3' end of the pre-rRNA coding region. We report here the purification to molecular homogeneity of a nuclear factor which specifically interacts with the Sal box element. Addition of the isolated protein to S-100 extracts which contain low levels of the Sal box-binding protein and are therefore termination incompetent restores terminating activity, indicating that this protein is a polymerase I-specific transcription termination factor. The purified protein (termed TTFI) has a molecular weight of approximately 105,000 on sodium dodecyl sulfate-polyacrylamide gels. Mild proteolysis generates a relatively protease-resistant core which still specifically recognizes its target sequence. However, the termination activity has been lost, suggesting that the interaction with the DNA and the interaction with the transcription apparatus reside in different protein domains.

The mouse ribosomal gene terminator consists of three functionally separable sequence elements.

The structural requirements for 3' end formation of mouse pre-rRNA have been studied. Three sequence elements are shown to be required for accurate and efficient transcription termination by RNA polymerase I (pol I) assayed both in a cell-free transcription system and in vivo after transfection of rDNA minigene constructs into 3T6 cells. The essential termination signal is the previously identified 18-bp conserved element (AGGTCGACCAGATTANTCCG) that contains a SalI restriction site. This sequence motif (the 'Sal box') interacts with a specific nuclear protein that directs transcription termination. Here we demonstrate that the 'Sal box' sequence motif is sufficient for termination of pol I transcripts and the release of the nascent RNA chains from the template. However, in addition to this termination signal, pyrimidine-rich sequences flanking the box at the 5' and 3' side play a role in the efficient and correct formation of authentic pre-rRNA termini. Downstream sequences contribute to the efficiency of the termination reaction, whereas the position of 3' end formation (i.e. 21 bp upstream of the 'Sal box') is affected by 5' flanking regions. These flanking regions are recognized by at least two different nuclear factors which specifically bind to DNA sequences located upstream and downstream of the 'Sal box'.