Biomedical subjects

S Müller

Publications and source records attributed to S Müller.

At least 181 records · Page 10Linked to original sources

PubMed1999

Influence of severe combined immunodeficiency phenotype on the outcome of HLA non-identical, T-cell-depleted bone marrow transplantation: a retrospective European survey from the European group for bone marrow transplantation and the european society for immunodeficiency.

We analyzed the outcomes of 214 HLA non-identical T-cell-depleted bone marrow transplantations (BMTs), performed in 178 consecutive patients for treatment of severe combined immunodeficiencies (SCID). Patients were treated in 18 European centers between 1981 and March 1995. SCID variants, that is, absence of T and B lymphocytes (B-) or absence of T cells with presence of B lymphocytes (B+) were found to have a major influence on outcome. The disease-free survival was significantly better for patients with B+ SCID (60%) as compared with patients with B- SCID (35%) (P =.002), with a median follow-up of 57 months and 52 months, respectively. Other factors associated with a poor prognosis were the presence of a lung infection before BMT (odds ratio = 2.47 [1.99-2.94]) and the use of monoclonal antibodies for T-cell depletion of the graft (odds ratio = 1.67 [1. 18-2.15]). Additional factors influencing outcome were age at BMT (<6 months) and period during which BMT was performed. Better results were achieved after 1991. Reduced survival of patients with B- SCID was associated with a higher incidence of early deaths from infection, a diminished rate of marrow engraftment, a trend to a higher incidence of chronic graft-versus-host disease, and slower kinetics of T/B immune function development. In both groups of patients, the use of busulfan (8 mg/kg total dose) and cyclophosphamide (200 mg/kg total dose) as a conditioning regimen provided the best cure rate (74% for patients with B+ SCID and 43% for patients with B- SCID, respectively), although results were not statistically significantly different from other regimens. This retrospective analysis should lead to the design of adapted measures to the performance of HLA non-identical BMT in patients with distinct SCID conditions.

Age Factors↗

PubMed1999

Improved high-frequency transthoracic flow velocity measurement in the left anterior descending coronary artery after intravenous peripheral injection of levovist.

New ultrasonic technology allows noninvasive measurement of the flow in the distal left anterior descending coronary artery. The goal of this study was to validate transthoracic determination of coronary flow velocity with the intracoronary Doppler flow wire technique. In 20 patients with normal coronary arteries, 2 intracoronary and 2 comparative transthoracic Doppler measurements (TTDMs) of the average peak velocity (APV) and the mean systolic and diastolic velocities were performed. The diastolic/systolic ratio was calculated. Blood flow velocity was determined in the distal left anterior descending coronary artery with a Doppler guide wire. Color Doppler and subsequent pulsed wave Doppler readings in an optimal left lateral position were available within 1 hour after completion of the invasive examinations. TTDM were performed during continuous administration of 2.0 g of contrast agent. A modified apical view was obtained from the fourth or fifth intercostal space, and a high-frequency transducer was used (7 MHz for 2-dimensional and 6 MHz for color Doppler imaging; 3.5 MHz for pulsed wave Doppler readings). The Doppler flow signal quality was graded from I to III (I = no flow mapping obtainable, II = poor quality, III = Doppler signals with a well-defined outline). In 13 (65%) patients, 26 TTDMs revealed signal quality of grade III. APV was calculated to be within normal limits (APVecho = 19.96 +/- 7.62 cm/s vs APVinvasive = 20.77 +/- 7.87 cm/s). APVecho correlated well with APVinvasive (r = 0.85, y = 0.82x + 2.85, P <.001). The mean difference between APVecho and APVinvasive (Bias) was -0.81 +/- 4.23 cm/s. No correlation was found between invasive and noninvasive measurements of diastolic/systolic velocity ratios (P >.05). High-frequency TTDM provides reliable data on APV in the majority of patients. It has the potential to be introduced as a relevant screening test for follow-up of patients after interventional treatment.

Blood Flow Velocity↗

PubMed1999

Mesoderm-determining transcription in Drosophila is alleviated by mutations in TAF(II)60 and TAF(II)110.

In Drosophila, a coordinate interplay between the Rel transcription factor Dorsal and the basic Helix-Loop-Helix transcription factor Twist initiates mesoderm formation by activating the zygotic expression of mesoderm-determining genes. Here, we show that TBP-associated-factors (TAF(II)s) within the basal transcription factor TFIID mediate transcriptional activation by Dorsal and Twist. Dorsal interacts with TAF(II)110 and TAF(II)60, while Twist contacts TAF(II)110. The TAF(II):activator interactions mediate simple and synergistic transactivation by Dorsal and Twist in vitro. Mutations in TAF(II)60 or TAF(II)110 alleviate the transcription of Dorsal and Twist target genes. Gene dosage assays imply that an interplay of Dorsal and Twist with TAF(II)110 is critically required for the activation of mesoderm-determining gene expression in the Drosophila embryo. The results provide evidence that TAF(II)-subunits within the TFIID complex play an important role during the molecular events leading to initiation of mesoderm formation in Drosophila.

Animals↗

PubMed1999

Assessment of complex peptide degradation pathways via structured multicompartmental modeling approaches: the metabolism of dynorphin A1-13 and related fragments in human plasma.

Peptide metabolic pathways in blood or other tissues are often complex because multiple enzyme systems are involved in the degradation of parent drug and its metabolites. Michaelis-Menten-type studies with isolated enzymes have been frequently employed for evaluating the metabolism of peptides. Alternatively, studies with selective enzyme inhibitors or the evaluation of the area under the drug- or metabolite-time profiles have been employed. We tested in this study the usefulness of a multicompartmental pharmacokinetic approach for the assessment of the apparent first-order metabolism of dynorphin A1-13 up to the fourth metabolite generation in human plasma. This multicompartmental kinetic analysis proved instrumental in clarifying ambiguous degradation pathways not easily detectable by the other methods of assessment (enzyme inhibition studies and noncompartmental analysis) because of the lack of specific enzyme inhibitors or specificity problems of the analytical technique employed. The proposed multicompartmental fitting approach was also highly suitable to verify the overall metabolic pathways suggested by the other methods up to the fourth metabolite by testing whether the rate constants obtained by these methods are suitable to describe the overall degradation profile after Dyn A1-13 degradation. Local sensitivity analysis for the degradation of DYNA 1-13 revealed that the model was, however, not able to adequately identify on its own all of the parameters involved in the degradation of dynorphin A1-13. Thus, the method proved beneficial in evaluating and testing the correctness of the overall degradation pathways suggested by other methods.

Algorithms↗

PubMed1999

Definition of a critical T cell threshold for prevention of GVHD after HLA non-identical PBPC transplantation in children.

The aim of this study was to reduce the rate of graft failure after HLA non-identical stem cell transplantation by using G-CSF mobilized CD34+ peripheral blood progenitor cells (PBPC), either in combination with bone marrow or as single grafts. To prevent GVHD, PBPC were highly purified, resulting in a 5 to 6 log T cell depletion. In additon to T cell depletion no further GVHD prophylaxis was used. We transplanted 23 pediatric patients with life-threatening malignant or non-malignant hematological disorders, who had no available matched donor. Engraftment was obtained in 18 of 21 evaluable patients. Five patients developed acute GVHD of grade II and III, which became chronic in four cases and was fatal in four. The use of highly purified PBPC allowed the exact quantification of residual T cells in the grafts and a strict correlation between the residual T cell load and the development of GVHD was observed: patients with GVHD had received numbers of T cells between 8 and 20 x 104/kg, whereas patients without GVHD were grafted with T cell numbers ranging from 0.7 to 6.0 x 104/kg. We therefore clearly demonstrate that a residual T cell content of <5 x 104/kg is safe for prevention of GVHD after HLA non-identical PBPC transplantation in children.

Adolescent↗

PubMed1999

Lipodystrophia centrifugalis abdominalis infantilis in a 4-year-old Caucasian girl: association with partial IgA deficiency and autoantibodies.

We report the third case of lipodystrophia centrifugalis abdominalis outside East Asia. A 4-year-old Caucasian girl developed an area of bluish erythema on the left side of the lower abdomen which spread centrifugally to the umbilical and inguinal areas with depression of the skin resulting from the loss of subcutaneous fat, surrounded by an erythematous border. This unusual skin disease was characterized by clinical and histological examination. Laboratory tests revealed a partial IgA deficiency, antinuclear antibodies and IgG antibodies against gliadin.

Abdomen↗

PubMed1999

A child with localized vulval pemphigoid and IgG autoantibodies targeting the C-terminus of collagen XVII/BP180.

Localized vulval pemphigoid of childhood (LVPC) has previously been reported in six girls. Clinical features and immunopathological data have suggested it to be a morphological variant of bullous pemphigoid. Epitope targets of the autoantibodies of these patients have not been defined in detail. We describe a 9-year-old girl with possible cicatricial LVPC and circulating IgG antibodies directed against native collagen XVII/BP180, its 120-kDa soluble ectodomain and against the C-terminus of collagen XVII/BP180. No reactivity was detected towards the NC16A domain of collagen XVII/BP180. Linear IgG and C3 deposits were found along the cutaneous basement membrane zone. On 1 mol/L salt-split skin, IgG autoantibodies were shown to bind to the epidermis, and the HLA type II allele DQB1*0301, a marker with significantly increased occurrence in patients with ocular and oral cicatricial pemphigoid, was identified in this patient. Our data suggest that LVPC is a variant of bullous pemphigoid in which direct immunofluorescence microscopy combined with immunoblot analysis can deliver valuable diagnostic information for differential diagnosis. However, differentiation between the scarring and non-scarring course of the disease cannot be made with the present diagnostic markers and therefore careful follow-up of patients with LVPC is required.

Autoantibodies↗

PubMed1999

Kinetics and extent of protein tyrosine kinase activation in individual T cells upon antigenic stimulation.

Using human CD4+ T-cell clones and peptide-pulsed antigen-presenting cells (APC) we measured, at the single cell level, different steps in the T-cell activation cascade. Simultaneous analysis of T-cell antigen receptor (TCR) down-regulation and interferon-gamma (IFN-gamma) production shows that both the level of TCR occupancy and the amount of IFN-gamma produced by single T cells increase in an antigen dose-dependent fashion. Conversely, commitment of T cells to IFN-gamma production does not occur as soon as a defined number of TCR have been engaged, but requires the same duration of sustained signalling at low as well as at high antigen concentrations. Measurement of phosphotyrosine levels by flow cytometry reveals that, upon conjugation with APC, individual T cells undergo an antigen dose-dependent activation of protein tyrosine kinases (PTK), which parallels the level of TCR occupancy. In antigen-stimulated T cells the increased phosphotyrosine staining is localized in the area of contact with APC, as shown by confocal microscopy. PTK activation is sustained for at least 2 hr after conjugation, and is required to maintain a sustained increase in intracellular Ca2+ concentration. Our results show, for the first time, a direct correlation between the level of TCR occupancy and the activation of PTK in individual T cells and offer an explanation for how the number of triggered TCR can be 'counted' and integrated in a corresponding biological response.

Antigen-Presenting Cells↗

PubMed1999

Secretion of human meprin from intestinal epithelial cells depends on differential expression of the alpha and beta subunits.

Human meprin (N-benzoyl-l-tyrosyl-p-aminobenzoic acid hydrolase, EC 3.4.24.18), an astacin-type metalloprotease, is expressed by intestinal epithelial cells as a dimeric protein complex of alpha and beta subunits. In transfected cells, intracellular proteolytic removal of the membrane anchor from the alpha subunit results in its secretion, while the beta subunit and alpha/beta heterodimers are retained at the cell membrane. We investigated the consequence of differential intracellular processing of alpha and beta subunits in the human small and large intestine using subunit-specific immunohistochemistry, in situ hybridization and biosynthetic studies in organ culture. In the ileum, both subunits localize to the brush-border membrane of villus enterocytes. In contrast, the beta subunit is not expressed in the colon, which leads to the secretion of the alpha subunit. We conclude that differential expression of meprin alpha and beta subunits is a unique means of targeting the proteolytic activity of the alpha subunit either to the brush-border membrane in the ileum or to the lumen in the colon, suggesting dual functions of cell-associated and luminal meprin. Meprin alpha and beta subunits are also coexpressed in distinct lamina propria leukocytes, suggesting an additional role for this protease in leukocyte function in the intestinal mucosa.

Colon↗

PubMed1999

Ascaridia galli fatty acid-binding protein, a member of the nematode polyprotein allergens family.

A fatty acid-binding protein from the nematode Ascaridia galli was characterized. The gene was isolated and recombinantly expressed in Escherichia coli. According to the deduced amino acid sequence A. galli fatty acid-binding protein (AgFABP) belongs to the family of nematode polyprotein allergens, as shown by Western blotting and PCR analysis with genomic DNA and cDNA. Both native and recombinant proteins bind fatty acids and retinoids with high affinity. The fluorescent fatty acid analogue 11-[(5-dimethylaminonaphthalene-1-sulfonyl)amino] undecanoic acid (DAUDA) shows substantial changes in its emission spectrum when bound to AgFABP; this binding is reversed by fatty acids such as oleate. Moreover, changes of the intrinsic fluorescence of retinol and retinoic acid confirm retinoid binding activity of AgFABP. Fluorescence titration experiments with DAUDA indicate stoichiometric binding to a single binding site per monomer unit with affinities (Kd) of 1.6 and 1.8 x 10(-7) m for native and the recombinant protein, respectively. The apparent binding affinities of the nonfluorescent ligands were calculated in displacement experiments with DAUDA and values in the same range were obtained for myristic, palmitic, oleic, linoleic, arachidonic and retinoic acid. Additionally, the binding affinity of AgFABP for oleate and palmitate was determined by direct and indirect radiochemical analysis and the values obtained were similar to those from the fluorescent experiments. Both proteins show a preference for the binding of long-chain saturated and unsaturated fatty acids, but not for short chain (C3-C12) and branched fatty acids, cholesterol and tryptophan.

Allergens↗

PubMed1999

Impact of amino acids 22-27 of Rho-subfamily GTPases on glucosylation by the large clostridial cytotoxins TcsL-1522, TcdB-1470 and TcdB-8864.

Here we report data describing some principles of the interaction between small GTP-binding proteins and large Clostridial cytotoxins (LCTs). Our investigation was based on the differential glucosylation of Rac1 versus RhoA by LCTs TcsL-1522, TcdB-1470 and TcdB-8864. Chimeric RhoA/Rac1 proteins and GTPases mutated at defined regions or single amino acids were used as substrates. Starting with chimeric Rac/Rho proteins we demonstrated that proteins containing the N-terminal 73 amino acids of Rac1 (but not those of RhoA) were efficiently glucosylated. Within this stretch, three regions differ significantly in Rac1 and RhoA. Regions containing amino acids 41-45 and 50-54 had no effect on toxin induced glucosylation, whereas amino acids 22-27 had a drastic impact on the potential of all three toxins to covalently modify the GTPases. Point mutations K25T of RhoA (numbering according to Rac1) and K27A of Cdc42 significantly increased glucosylation by the cytotoxins; introduction of lysines at the equivalent positions of Rac1 hindered modification. Our experiments demonstrate the influence of this charged residue on GTPase-LCT interactions. Amino acids 22-27 are part of the transition between the alpha1-helix to the switch I region of small GTP-binding proteins; both are known structures for specificity determination of the interactions with physiologic partners. Comparing these structures with data from our investigation we suggest that TcsL-1522, TcdB-1470 and TcdB-8864 mimic aspects of the physiologic interactions of small GTP-binding proteins.

Amino Acid Sequence↗

PubMed1999

Simultaneous contralateral testicular metastasis from a renal clear cell carcinoma.

The case of a 66-year-old male with a right renal cell carcinoma and a left testicular mass is reported. Radical nephrectomy and contralateral orchidectomy were performed. Histology revealed a metastasis of the renal cell carcinoma of clear cell type into the left testis. The patient died seven months post-operatively of disseminated lung metastases. The case demonstrates the multi-ocular metastatic potential of renal cell carcinoma.

Adenocarcinoma, Clear Cell↗

PubMed1999

Laufband (treadmill) therapy in incomplete paraplegia and tetraplegia.

Recent reports indicate that intensive training of upright walking on a treadmill (German: Laufband, LB), significantly improves walking capability in spinal cord-damaged persons. The aids provided initially are body weight support by a harness and passive setting of one or both limbs by therapists. To facilitate stepping and evoke motor automatisms, "rules of spinal locomotion" need to be applied during training. The effects of this novel locomotion therapy on patients with chronic and acute incomplete paralysis are summarized and discussed here. Many patients with chronic paralysis, still wheelchair-bound and not capable of walking without help from others, became independent and learned to walk for some distance without help. Assessment of voluntary muscle activity in resting position before and after the period of therapy often showed only small increases, rendering the involvement of complex motor reflexes (motor programs) and better utilization of remaining muscle function during walking as main sources for the improvements in locomotion. This idea is supported by electromyographic recordings. Follow-up assessments performed 0.5 to 6.5 years after discharge from the hospital show that the significant improvements achieved by LB-therapy in patients with initially chronic paralysis can be maintained under domestic surrounding. Patients with initially acute paralysis improved their walking capabilities even further. It is suggested that LB therapy may be generally applied in the motor rehabilitation of persons with acute and chronic incomplete paraplegia and tetraplegia. Its use in other diseases is discussed.

Adult↗

PubMed1999

Probing the molecular environment of membrane proteins in vivo.

The split-Ubiquitin (split-Ub) technique was used to map the molecular environment of a membrane protein in vivo. Cub, the C-terminal half of Ub, was attached to Sec63p, and Nub, the N-terminal half of Ub, was attached to a selection of differently localized proteins of the yeast Saccharomyces cerevisiae. The efficiency of the Nub and Cub reassembly to the quasi-native Ub reflects the proximity between Sec63-Cub and the Nub-labeled proteins. By using a modified Ura3p as the reporter that is released from Cub, the local concentration between Sec63-Cub-RUra3p and the different Nub-constructs could be translated into the growth rate of yeast cells on media lacking uracil. We show that Sec63p interacts with Sec62p and Sec61p in vivo. Ssh1p is more distant to Sec63p than its close sequence homologue Sec61p. Employing Nub- and Cub-labeled versions of Ste14p, an enzyme of the protein isoprenylation pathway, we conclude that Ste14p is a membrane protein of the ER. Using Sec63p as a reference, a gradient of local concentrations of different t- and v-SNARES could be visualized in the living cell. The RUra3p reporter should further allow the selection of new binding partners of Sec63p and the selection of molecules or cellular conditions that interfere with the binding between Sec63p and one of its known partners.

Base Sequence↗

PubMed1999

Transcriptional regulation of genes encoding the selenium-free [NiFe]-hydrogenases in the archaeon Methanococcus voltae involves positive and negative control elements.

Methanococcus voltae harbors genetic information for two pairs of homologous [NiFe]-hydrogenases. Two of the enzymes contain selenocysteine, while the other two gene groups encode apparent isoenzymes that carry cysteinyl residues in the homologous positions. The genes coding for the selenium-free enzymes, frc and vhc, are expressed only under selenium limitation. They are transcribed out of a common intergenic region. A series of deletions made in the intergenic region localized a common negative regulatory element for the vhc and frc promoters as well as two activator elements that are specific for each of the two transcription units. Repeated sequences, partially overlapping the frc promoter, were also detected. Mutations in these repeated heptanucleotide sequences led to a weak induction of a reporter gene under the control of the frc promoters in the presence of selenium. This result suggests that the heptamer repeats contribute to the negative regulation of the frc transcription unit.

Archaeal Proteins↗

PubMed1999

Studies on structural changes of the carotid arteries and the heart in asymptomatic renal transplant recipients.

BACKGROUND: The present study was designed to characterize early structural changes of large arteries in renal transplant recipients with no clinical evidence of cardiovascular disease and normal blood pressure values, and to analyse the relationship between arterial alterations and those of the heart. METHODS: Intima media thickness and atherosclerotic plaques of the carotid arteries as well as left ventricular geometry and function were examined in 35 asymtomatic renal transplant recipients and 29 age- and sex-matched healthy controls by high resolution B-mode ultrasound and by echocardiography. RESULTS: Intima-media thickness of the carotid arteries was significantly higher in renal transplant recipients (1.21+/-0.08 mm) than in healthy controls (0.74+/-0.04 mm) (P<0.001). Atherosclerotic plaques were found in the majority of renal transplant recipients (71% vs 14% in healthy controls, P<0.001). Left ventricular mass index was significantly increased in the group of renal transplant recipients (264+/-13 g, 146+/-7 g/m2) when compared with healthy controls (155+/-8 g, 83+/-4 g/m2) (P<0.001). Multiple regression analysis in renal transplant recipients showed that intima media thickness of the carotid arteries was significantly related to left ventricular mass index (P<0.02), but not to age, blood pressure, body mass index, serum creatinine, cholesterol and lipoprotein (a) levels. In the group of healthy controls, intima-media thickness of the carotid artery was related to age (P<0.002), but not to left ventricular mass index or the other independent variables. CONCLUSIONS: The present study documents pronounced intima-media thickening in asymptomatic renal transplant recipients. Atherosclerotic lesions are present in most renal transplant recipients with no clinical evidence of cardiovascular disease. We observed a parallelism between arterial wall thickening and left ventricular hypertrophy, although blood pressure levels were normal during haemodialysis therapy and after renal transplantation.

Adult↗

PubMed1999

Viral immediate-early proteins abrogate the modification by SUMO-1 of PML and Sp100 proteins, correlating with nuclear body disruption.

PML nuclear bodies (NBs) are subnuclear structures whose integrity is compromised in certain human diseases, including leukemia and neurodegenerative disorders. Infection by a number of DNA viruses similarly triggers the reorganization of these structures, suggesting an important role for the NBs in the viral infection process. While expression of the adenovirus E4 ORF3 protein leads to only a moderate redistribution of PML to filamentous structures, the herpes simplex virus (HSV) ICP0 protein and the cytomegalovirus (CMV) IE1 protein both induce a complete disruption of the NB structure. Recently, we and others have shown that the NB proteins PML and Sp100 are posttranslationally modified by covalent linkage with the ubiquitin-related SUMO-1 protein and that this modification may promote the assembly of these structures. Here we show that the HSV ICP0 and CMV IE1 proteins specifically abrogate the SUMO-1 modification of PML and Sp100, whereas the adenovirus E4 ORF3 protein does not affect this process. The potential of ICP0 and IE1 to alter SUMO-1 modification is directly linked to their capacity to disassemble NBs, thus strengthening the role for SUMO-1 conjugation in maintenance of the structural integrity of the NBs. This observation supports a model in which ICP0 and IE1 disrupt the NBs either by preventing the formation or by degrading of the SUMO-1-modified PML and Sp100 protein species. Finally, we show that the IE1 protein itself is a substrate for SUMO-1 modification, thus representing the first viral protein found to undergo this new type of posttranslational modification.

Antigens, Nuclear↗

PubMed1999

Aspiration: a possible severe complication in colonoscopy preparation of elderly people by orthograde intestine lavage.

Total gut lavage is a widely recommended method in preparation for colonoscopy and there are almost no reports of severe complications in the literature. Application of orthograde lavage by a nasogastric tube may be necessary in disorientated patients, assisted by slight medical sedation, if necessary. Despite absolutely correct appliance of the method, a case of severe aspiration with subsequent hypoxemia and stroke in a senile female patient, suffering from a common hiatal hernia, is described.

Aged↗