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Thomas Schmidt

Publications and source records attributed to Thomas Schmidt.

At least 19 recordsLinked to original sources
PubMed2007

Mobilization and evolutionary history of miniature inverted-repeat transposable elements (MITEs) in Beta vulgaris L.

We have identified three families of miniature inverted-repeat transposable elements (VulMITEs) in the genome of sugar beet (Beta vulgaris L.), evidently derived from a member of the Vulmar family of mariner transposons. While VulMITEs I are typical stowaway-like MITEs, VulMITEs II and VulMITEs III are rearranged stowaway elements of increased size. The integration of divergent moderately and highly repetitive sequences into VulMITEs II and, in particular in VulMITEs III, respectively, shows that amplification of repetitive DNA by MITEs contribute to the increase of genome size with possible implications for plant genome evolution. Fluorescent in-situ hybridization (FISH), for the first time visualizing stowaway MITE distribution on plant chromosomes, revealed a dispersed localization of VulMITEs along all B. vulgaris chromosomes. Analysis of the flanking sequences identified a dispersed repeat as target site for the integration of the stowaway element VulMITE I. Recent transposition of VulMITE I, which most likely occurred during the domestication of cultivated beets, was concluded from insertional polymorphisms between different B. vulgaris cultivars and species.

Base Sequence↗
PubMed2007

Molecular organization of terminal repetitive DNA in Beta species.

We have isolated families of subtelomeric satellite DNA sequences from species of four sections of the genus Beta and from spinach, a related Chenopodiaceae. Twenty-five clones were sequenced and representative repeats of each family were characterized by Southern blotting and FISH. The families of ApaI restriction satellite repeats were designated pAv34, pAc34, the families of RsaI repeats pRp34, pRn34 and pRs34. The repeating units are 344-362 bp long and 45.7-98.8% homologous with a clear species-specific divergence. Each satellite monomer consists of two subrepeats SR1 and SR2 of 165-184 bp, respectively. The repeats of each subrepeat group are highly identical across species, but share only a homology of 40.8-54.8% with members of the other subrepeat group. Two evolutionary steps could be supposed in the phylogeny of the subtelomeric satellite family: the diversification of an ancestor satellite into groups representing SR1 and SR2 in the progenitor of Beta and Spinacea species, followed by the dimerization and diversification of the resulting 360 bp repeats into section-specific satellite DNA families during species radiation. The chromosomal localization of telomeric, subtelomeric and rDNA tandem repeats was investigated by multi-colour FISH. High-resolution analysis by fibre FISH revealed a unique physical organization of B. vulgaris chromosome ends with telomeric DNA and subtelomeric satellites extending over a maximum of 63 kb and 125 kb, respectively.

Base Sequence↗
PubMed2006

Immunolocalization of phospho-S6 kinases: a new way to detect mitosis in tissue sections and in cell culture.

During a study on the mTor pathway in the rat kidney we observed a striking increase of the phosphorylation of the S6 kinase in mitosis. In cryostat sections of perfusion-fixed tissue mitotic cells appeared as bright spots in immunofluorescence using an antibody specific for the phosphorylation site Thr421/Ser424. They were easily spotted in overviews with the objective 4x and 10x. Immunofluorescence was weak during the interphase. During the prophase it increased in both the nucleus and the cytoplasm and it remained bright during the subsequent phases of mitosis. All mitotic cells which were found in tubules and in the interstitium of the kidney using a chromatin stain displayed the bright immunofluorescence for phospho-S6 kinase. The same phenomenon was observed in rat liver and in mouse kidney as well as in a human cell line. Provided a rapid fixation, mitotic cells could be identified with the immunoperoxidase technique in paraffin sections of immersion-fixed tissue. This is the first report of phosphorylation of S6 kinase during mitosis in vivo. Thus, immunohistochemistry with anti-phospho-S6 kinase (Thr421/Ser424) appears to provide a convenient way to detect mitotic cells at low magnification.

Animals↗
PubMed2006

Percutaneous implantation of the CoreValve self-expanding valve prosthesis in high-risk patients with aortic valve disease: the Siegburg first-in-man study.

BACKGROUND: The morbidity and mortality of surgical aortic valve replacement are increased in elderly patients with multiple high-risk comorbid conditions. Therefore, a prospective, single-center, nonrandomized study was performed in high-risk patients with aortic valve disease to evaluate the feasibility and safety of percutaneous implantation of a novel self-expanding aortic valve bioprosthesis (CoreValve). METHODS AND RESULTS: Symptomatic high-risk patients with an aortic valve area <1 cm2 were considered for enrollment. CoreValve implantation was performed under general anesthesia with extracorporeal support using the retrograde approach. Clinical follow-up and transthoracic echocardiography were performed after the procedure and at days 15 and 30 after device implantation to evaluate short-term patient and device outcomes. A total of 25 patients with symptomatic aortic valve stenosis (mean gradient before implantation, 44.2+/-10.8 mm Hg) and multiple comorbidities (median logistic EuroScore, 11.0%) were enrolled. Device success and procedural success were achieved in 22 (88%) and 21 (84%) patients, respectively. Successful device implantation resulted in a marked reduction in the aortic valve gradients (mean gradient after implantation, 12.4+/-3.0 mm Hg; P<0.0001). The mean aortic regurgitation grade was unchanged. Major in-hospital cardiovascular and cerebral events occurred in 8 patients (32%), including mortality in 5 patients (20%). Among 18 patients with device success surviving to discharge, no adverse events occurred within 30 days after leaving the hospital. CONCLUSIONS: Percutaneous implantation of the self-expanding CoreValve aortic valve prosthesis in high-risk patients with aortic stenosis with or without aortic regurgitation is feasible and, when successful, results in marked hemodynamic and clinical improvement.

Aged↗
PubMed2006

Single-molecule diffusion reveals similar mobility for the Lck, H-ras, and K-ras membrane anchors.

Recent evidence on the occurrence of small (5-700 nm diameter) lipid microdomains in the exoplasmic leaflet of the plasma membrane has evoked interest in the possibility that similar domains may also be present in the cytoplasmic leaflet of the plasma membrane. However, current knowledge about these "lipid rafts", in live cells is limited. One way to obtain insight into the occurrence and the size of lipid rafts is the use of single-molecule microscopy, which allows one to study the diffusive motion of individual molecules with high positional and temporal accuracy. Using this technique, we compared the diffusion behavior of the Lck membrane anchor, which has a high affinity for lipid rafts, to the diffusion behavior of the K-Ras membrane anchor, which has negligible affinity for rafts and compared the results with those of the H-Ras membrane anchor. Surprisingly, we found only minor differences in the diffusion behavior of the various lipid anchors, indicating that putative cytoplasmic leaflet lipid rafts would have to be small (<137 nm diameter) and do not affect the mobility of membrane-anchored molecules much on timescales up to 60 ms.

3T3 Cells↗
PubMed2006

Angiographic results of the first human experience with the Biolimus A9 drug-eluting stent for de novo coronary lesions.

This report describes angiographic findings of the first-in-human evaluation of the Biolimus A9 drug-eluting stent (Biolimus stent) in the treatment of noncomplex coronary lesions. In total, 120 patients with 122 de novo coronary lesions (2.75- to 4.00-mm vessels, < or = 24-mm lesion length) were prospectively randomized in a 2:1 ratio to receive the Biolimus stent (n = 80, 82 lesions) or the control uncoated stent (n = 40). Baseline lesion and angiographic characteristics were similar between groups. At 6-month follow-up, late lumen loss was significantly decreased with the Biolimus stent in the stent (0.26 +/- 0.43 vs 0.74 +/- 0.45 mm, p < 0.001) and in the segment (0.14 +/- 0.45 vs 0.40 +/- 0.41 mm, p = 0.004). In-stent restenosis was 3.9% in the Biolimus stent group versus 7.7% in the control group (p = 0.40). There was no exaggerated hyperplasia at the proximal and/or distal edge of the stent.

Blood Vessel Prosthesis Implantation↗
PubMed2006

Electron beam irradiation of poly(vinyl methyl ether) films. 2. Temperature-dependent swelling behavior.

Temperature-sensitive hydrogel films were synthesized by electron beam irradiation of poly(vinyl methyl ether) (PVME) on silicon (Si/SiO(2)) substrates and gold (Au) coated glass slides. The temperature-dependent swelling behavior of the films in aqueous solution was characterized by in situ spectroscopic ellipsometry and a combination of surface plasmon resonance (SPR) and optical waveguide spectroscopy (OWS). The results of both techniques are compared. The suitability of both techniques for the characterization of the swelling behavior of thin hydrogel films is demonstrated. The volume swelling degree in the swollen state decreases with increasing radiation dose D. This is explained by the fact that the number of formed polymeric radicals, and hence cross-linking density, increases with D. Above the phase-transition temperature, the swelling degrees were independent of D, slightly above 1. The swelling/deswelling process was fully reversible and is mainly directed perpendicular to the substrate surface. The phase-transition temperature was determined to be T(cr) approximately 33 degrees C. However, T(cr) slightly decreases with increasing D and increasing film thickness d.

Journal Article↗
PubMed2006

Learning under anesthesia: checking the light in the fridge? Commentary on Deeprose and Andrade (2006).

Research on learning under anesthesia has focused on showing that learning is possible in the absence of awareness. However, a simple dissociation between learning and awareness is conclusive only under strong additional assumptions, and the actual state of consciousness of an anesthetized person is difficult to determine. Instead of trying to establish complete unconsciousness, one might employ gradual anesthesia to experimentally vary the level of consciousness in a controlled fashion, checking whether cognitive processes exist that can change in opposite direction to measures of awareness.

Anesthesia↗
PubMed2006

Use of Taxus polymer-coated paclitaxel-eluting stents for treatment of in-stent restenosis in real world patients: results of clinical and angiographic follow-up at six months in a single-center registry.

OBJECTIVE: To evaluate the safety and efficacy of Taxus paclitaxel-eluting stents in a real world group of unselected patients with coronary in-stent restenosis (ISR) lesions. METHODS: This is a prospective single-center registry of a consecutive series of 94 patients with 104 ISR lesions, without previous brachytherapy, over a period of 1 year. Quantitative coronary angiographic analyses were performed at baseline and at 6-month angiographic follow-up. Clinical follow-up were obtained at 6 months. RESULTS: Pre-intervention mean reference vessel diameter was 2.62 +/- 0.50 mm and mean lesion length was 13.95 +/- 6.78 mm. Baseline ISR patterns were mostly either Type I focal (32.7%) or Type II diffuse intrastent (48.1%). At 6-month angiographic follow-up, the in-stent and in-segment binary restenosis was 3.8% (4/105) and 7.6% (8/105) respectively, and the in-stent and in-segment late loss was 0.30 +/- 0.50 mm and 0.57 +/- 0.54 mm, respectively. Seven of these eight restenosed lesions had a diffuse or proliferative ISR pattern prior to intervention. Lesions that restenosed had longer mean stent length per lesion (37.3 mm vs. 22.5 mm in nonrestenosed group; P = 0.001) and more likely to have had a pattern of total occlusion pre-intervention (25.0% vs. 3.1% in nonrestenosed group; P = 0.046). At 6-month clinical follow-up, the MACE rate was 8.5% and target lesion revascularization rate was 7.4%. There was no death but subacute stent thrombosis occurred in 1 patient (1.1%) at 3 days after intervention. CONCLUSIONS: Paclitaxel-eluting Taxus stent for the treatment of ISR effectively suppresses recurrent neointimal proliferation, and was safe and efficacious at 6-month follow-up.

Aged↗
PubMed2006

Primes and targets in rapid chases: tracing sequential waves of motor activation.

Single-cell recordings have indicated that visual stimuli elicit rapid waves of neuronal activation that propagate so fast that they might be free of intracortical feedback. Here, the time course of feedforward activation was traced by measuring pointing responses to color targets preceded by color primes initiating either the same or opposite response. The early time course of priming effects was strictly time locked to prime onset and depended only on properties of the primes, but was independent of the onset times of the actual targets as well as the perceptual effects of targets on primes. Results indicated that nonoverlapping feedforward signals by primes and targets traverse the visuomotor system in a rapid chase, controlling associated motor responses in strict sequence.

Adult↗
PubMed2006

Criteria for unconscious cognition: three types of dissociation.

To demonstrate unconscious cognition, researchers commonly compare a direct measure (D) of awareness for a critical stimulus with an indirect measure (I) showing that the stimulus was cognitively processed at all. We discuss and empirically demonstrate three types of dissociation with distinct appearances in D-I plots, in which direct and indirect effects are plotted against each other in a shared effect size metric. Simple dissociations between D and I occur when I has some nonzero value and D is at chance level; the traditional requirement of zero awareness is necessary for this criterion only. Sensitivity dissociations only require that I be larger than D; double dissociations occur whensome experimental manipulation has opposite effects on I and D. We show that double dissociations require much weaker measurement assumptions than do other criteria. Several alternative approaches can be considered special cases of our framework.

Cognition↗
PubMed2006

Evaluation of a new polymer-coated paclitaxel-eluting stent for treatment of de novo lesions: six-month clinical and angiographic follow-up results of the APPLAUSE trial.

BACKGROUND: This trial assesses the safety and efficacy of the PicoElite stent (amg International GmbH, Raesfeld-Erle, Germany), a new paclitaxel-eluting polymer-based stent. METHODS: This is a first-in-man, single-center pilot trial that randomized 30 patients with 35 de novo coronary lesions in a 2:1 proportion to either the paclitaxel-eluting PicoElite stent (PES group: 20 patients with 24 lesions) or the bare metal ArthosPico stent (BMS group: 10 patients with 11 lesions). RESULTS: Baseline characteristics were similar in both groups, apart from younger patients in the PES group (mean age 63.5 years vs. 71.7 years in the BMS group; p = 0.032) and shorter lesion length in the PES group (9.56 mm vs. 14.25 mm in the BMS group; p = 0.02). In both groups, there was no difference in the primary endpoint of major adverse cardiac events (MACE) at 30-day follow up. There was a nonsignificant trend towards lower 6-month MACE and target lesion revascularization (TLR) rates in the PES group (10.5% PES vs. 40.0% in the BMS group for both; p = 0.143), and no stent thrombosis in the PES group. At 6-month angiographic follow up, the PES group demonstrated a significantly reduced in-stent binary restenosis rate (5.0% vs. 40.0%; p = 0.031), in-stent late loss (0.47 mm vs. 1.10 mm; p = 0.004), and in-segment late loss (0.72 mm vs. 1.16 mm; p = 0.016) as compared to the BMS group. CONCLUSIONS: The 6-month results of the APPLAUSE study demonstrate the safety and efficacy of the paclitaxel-eluting PicoElite stent for de novo lesions, with a significant reduction in late loss and a trend towards less TLR compared to a bare metal control.

Adult↗
PubMed2005

Sensitive detection of the redox state of copper proteins using fluorescence.

The blue copper protein azurin from Pseudomonas aeruginosa has been covalently labelled with the fluorescing dye Cy5. The optical spectrum of the azurin changes markedly with its redox state. These changes are reflected in the fluorescence intensity of the dye through fluorescence resonance energy transfer (FRET). This provides a sensitive way to monitor biological redox events. The method shown to work in the nanomolar range of protein concentrations, can be easily extended into the sub-nanomolar regime and holds promise for single-molecule detection.

Azurin↗
PubMed2005

The oxidation state of a protein observed molecule-by-molecule.

We report the observation of the redox state of the blue copper protein azurin on the single-molecule level. The fluorescence of a small fluorophore attached to the protein is modulated by the change in absorption of the copper center via fluorescence resonance energy transfer (FRET). In our model system, the fluorescence label Cy5 was coupled to azurin from Pseudomonas aeruginosa via cysteine K27C. The Cy5 fluorescence was partially quenched by the absorption of the copper center of azurin in its oxidized state. In the reduced state, absorption is negligible, and thus no quenching occurs. We report on single-molecule measurements, both in solution by using fluorescence correlation spectroscopy (FCS) combined with fluorescence intensity distribution analysis (FIDA), and on surfaces by using wide-field fluorescence microscopy.

Absorption↗
PubMed2005

Electron beam irradiation of poly(vinyl methyl ether) films: 1. Synthesis and film topography.

Temperature-sensitive hydrogel layers on silicon (Si) substrates were synthesized by electron beam irradiation of spin-coated poly(vinyl methyl ether) (PVME) films. The influences of the used solvent, the polymer concentration, and the spinning velocity on the homogeneity and the thickness of the PVME film were investigated. In the range of concentration c(p) = 1-15 wt% PVME in ethanol solution, homogeneous films with a thickness between d = 50 nm and 1.7 mum were obtained. The films were cross-linked by electron beam irradiation under inert atmosphere and analyzed by sol-gel-analysis. The results were compared with bulkgels formed by electron beam irradiation of PVME in the dry state. The film topography was analyzed by high-resolution field emission scanning electron microscopy and atomic force microscopy. An islandlike structure in the dry, swollen, and shrunken state of the hydrogel films was observed.

Journal Article↗
PubMed2005

Incidence, predictors, and outcome of thrombosis after successful implantation of drug-eluting stents.

CONTEXT: Traditionally, stent thrombosis has been regarded as a complication of percutaneous coronary interventions during the first 30 postprocedural days. However, delayed endothelialization associated with the implantation of drug-eluting stents may extend the risk of thrombosis beyond 30 days. Data are limited regarding the risks and the impact of this phenomenon outside clinical trials. OBJECTIVE: To evaluate the incidence, predictors, and clinical outcome of stent thrombosis after implantation of sirolimus-eluting and paclitaxel-eluting stents in routine clinical practice. DESIGN, SETTING, AND PATIENTS: Prospective observational cohort study conducted at 1 academic hospital and 2 community hospitals in Germany and Italy. A total of 2229 consecutive patients underwent successful implantation of sirolimus-eluting (1062 patients, 1996 lesions, 2272 stents) or paclitaxel-eluting (1167 patients, 1801 lesions, 2223 stents) stents between April 2002 and January 2004. INTERVENTIONS: Implantation of a drug-eluting stent (sirolimus or paclitaxel). All patients were pretreated with ticlopidine or clopidogrel and aspirin. Aspirin was continued indefinitely and clopidogrel or ticlopidine for at least 3 months after sirolimus-eluting and for at least 6 months after paclitaxel-eluting stent implantation. MAIN OUTCOME MEASURES: Subacute thrombosis (from procedure end through 30 days), late thrombosis (>30 days), and cumulative stent thrombosis. RESULTS: At 9-month follow-up, 29 patients (1.3%) had stent thrombosis (9 [0.8%] with sirolimus and 20 [1.7%] with paclitaxel; P = .09). Fourteen patients had subacute thrombosis (0.6%) and 15 patients had late thrombosis (0.7%). Among these 29 patients, 13 died (case fatality rate, 45%). Independent predictors of stent thrombosis were premature antiplatelet therapy discontinuation (hazard ratio [HR], 89.78; 95% CI, 29.90-269.60; P<.001), renal failure (HR, 6.49; 95% CI, 2.60-16.15; P<.001), bifurcation lesions (HR, 6.42; 95% CI, 2.93-14.07; P<.001), diabetes (HR, 3.71; 95% CI, 1.74-7.89; P = .001), and a lower ejection fraction (HR, 1.09; 95% CI, 1.05-1.36; P<.001 for each 10% decrease). CONCLUSIONS: The cumulative incidence of stent thrombosis 9 months after successful drug-eluting stent implantation in consecutive "real-world" patients was substantially higher than the rate reported in clinical trials. Premature antiplatelet therapy discontinuation, renal failure, bifurcation lesions, diabetes, and low ejection fraction were identified as predictors of thrombotic events.

Angioplasty, Balloon, Coronary↗
PubMed2005

Single-molecule diffusion measurements of H-Ras at the plasma membrane of live cells reveal microdomain localization upon activation.

Recent studies show that the partitioning of the small GTPase H-Ras in different types of membrane microdomains is dependent on guanosine 5'-triphosphate (GTP)-loading of H-Ras. Detailed knowledge about the in vivo dynamics of this phenomenon is limited. In this report, the effect of the activation of H-Ras on its microdomain localization was studied by single-molecule fluorescence microscopy. Individual human H-Ras molecules fused to the enhanced yellow fluorescent protein (eYFP) were imaged in the dorsal plasma membrane of live mouse cells and their diffusion behavior was analyzed. The diffusion of a constitutively inactive (S17N) and constitutively active (G12V) mutant of H-Ras was compared. Detailed analysis revealed that for both mutants a major, fast-diffusing population and a minor, slow-diffusing population were present. The slow-diffusing fraction of the active mutant was confined to 200 nm domains, which were not observed for the inactive mutant. In line with these results we observed that the slow-diffusing fraction of wild-type H-Ras became confined to 200 nm domains upon insulin-induced activation of wild-type H-Ras. This activation-dependent localization of H-Ras to 200 nm domains, for the first time directly detected in live cells, supports the proposed relationship between H-Ras microdomain localization and activation.

Animals↗