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D Schröder

Publications and source records attributed to D Schröder.

At least 19 recordsLinked to original sources
PubMed2003

[Temporomandibular disorders in juvenile patients with rheumatic diseases].

PURPOSE: The aim of the study was to investigate the incidence of temporomandibular disorders (TMD) in juvenile patients with rheumatic diseases. Furthermore, correlations between the degree of the rheumatic disease and the clinical symptoms were evaluated. MATERIAL AND METHODS: In a prospective investigation the temporomandibular joints of 48 children with rheumatic diseases were evaluated clinically regarding clicking, crepitation, pain, duration of the rheumatic disease, and the number of affected peripheral joints. The degree of rheumatic disease was assessed with Steinbrocker's classification. RESULTS: 26 patients (54.17%) showed clinical symptoms of TMD. No significant correlation was found between the degree of the rheumatic disease and the awareness of TMD. A high number of affected peripheral joints does not lead to a significant increase of TMD. A significant correlation between the duration of the rheumatic disease and TMD could be detected. A significant correlation between the duration of the rheumatic disease and clicking or crepitation was found ( p=0.011). CONCLUSION: Rheumatic diseases lead to a higher incidence of TMD in juvenile patients. A longer duration of rheumatic diseases leads to a higher incidence of TMD.

Adolescent↗
PubMed2003

Efficacy of a homeopathic Crataegus preparation compared with usual therapy for mild (NYHA II) cardiac insufficiency: results of an observational cohort study.

OBJECTIVES: To compare the efficacy of the homeopathic Crataegus preparation Cralonin for non-inferiority to standard treatment for mild cardiac insufficiency. METHODS: Multicentre non-randomised cohort study in patients aged 50-75 years in New York Heart Association class II. Patients received Cralonin (n=110) or ACE inhibitor/diuretics (n=102) for 8 weeks. To adjust for confounding by baseline factors, populations were stratified according to propensity score. After adjusting, there were no statistically significant differences between treatment groups. Treatment efficacy was assessed on 15 variables. A stringent non-inferiority criterion for the upper limit of the 97.5% one-sided confidence interval of the treatment difference was set to 0.2x the standard deviation (S.D.). RESULTS: Both treatment regimens improved scores on most variables studied, with the greatest effect on double product after exercise (average score reduction 15.4% with Cralonin vs. 16.0% for the control group). Stringent non-inferiority of Cralonin was demonstrated on 7 variables. Medium-stringent (0.5xS.D.) non-inferiority was indicated by 13 variables (exceptions: systolic blood pressure (BP) during exercise and diastolic BP at rest; for these, differences between treatments were not significant). Both treatments were well tolerated. CONCLUSION: The Crataegus-based preparation Cralonin is non-inferior to usual ACE inhibitor/diuretics treatment for mild cardiac insufficiency on all parameters except BP reduction.

Aged↗
PubMed2002

Application of the Weibull distribution to describe the vertical distribution of cesium-137 on a slope under permanent pasture in Luxembourg.

The application of solutions of the Advection-Dispersion-Equation (ADE) for soil profiles is sometimes questionable. An alternative method, based on the Weibull distribution, has been developed, which can approximate the vertical distribution of radiocesium (137Cs) and allows extrapolation to account for the complete inventory. The structure of the equation allows simple parameters describing the soil depth profile to be derived. Reliable estimates of the total 137Cs inventory can help to explain the lateral distribution. This equation was used to analyse the 137Cs-activities of Chernobyl fall-out measured on a slope under permanent pasture in Luxembourg.

Cesium Radioisotopes↗
PubMed2002

Genetic polymorphisms in the renin-angiotensin-aldosterone system associated with expression of left ventricular hypertrophy in hypertrophic cardiomyopathy: a study of five polymorphic genes in a family with a disease causing mutation in the myosin binding protein C gene.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is an inherited disease of the sarcomere characterised clinically by myocardial hypertrophy and its consequences. Phenotypic expression is heterogeneous even within families with the same aetiological mutation and may be influenced by additional genetic factors. OBJECTIVE: To determine the influence of genetic polymorphisms of the renin-angiotensin-aldosterone system (RAAS) on ECG and two dimensional echocardiographic left ventricular hypertrophy (LVH) in genetically identical patients with HCM. PATIENTS AND METHODS: Polymorphisms of five RAAS components were determined in 26 gene carriers from a single family with HCM caused by a previously identified myosin binding protein C mutation. Genotypes associated with a higher activation status of the RAAS were labelled "pro-LVH genotypes". RESULTS: There was a non-biased distribution of pro-LVH genotypes in the gene carriers. Those without pro-LVH genotypes did not manifest cardiac hypertrophy whereas gene carriers with pro-LVH genotypes did (mean (SD) left ventricular muscle mass 190 (48) v 320 (113), p = 0.002; interventricular septal thickness 11.5 (2.0) v 16.4 (6.7), p = 0.01; pathological ECG 0% (0 of 10) v 63% (10 of 16), respectively). Multivariate analysis controlling for age, sex, and hypertension confirmed an independent association between the presence of pro-LVH polymorphisms and left ventricular mass. When each polymorphism was assessed individually, carriers of each pro-LVH genotype had a significantly greater left ventricular mass than those with no pro-LVH mutation; these associations, with the exception of cardiac chymase A AA polymorphism (p = 0.06), remained significant in multivariate analysis. CONCLUSION: Genetic polymorphisms of the RAAS influence penetrance and degree of LVH in 26 gene carriers from one family with HCM caused by a myosin binding protein C mutation.

Age Factors↗
PubMed2001

Gas-phase properties and fragmentation behavior of cationic, dinuclear iron chloride clusters Fe(2)Cl(n)()(+) (n = 1-6).

Sector-field mass spectrometry is used to probe the fragmentation patterns of cationic dinuclear iron chloride clusters Fe(2)Cl(n)()(+) (n = 1-6). For the chlorine-rich, high-valent Fe(2)Cl(n)()(+) ions (n = 4-6), losses of atomic and molecular chlorine prevail in the unimolecular and collision-induced dissociation patterns. Instead, the chlorine deficient, formally low-valent Fe(2)Cl(n)()(+) clusters (n = 1-3) preferentially undergo unimolecular degradation to mononuclear FeCl(m)()(+) ions. In addition, photoionization is used to determine IE(Fe(2)Cl(6)) = 10.85 +/- 0.05 eV along with appearance energy measurements for the production of Fe(2)Cl(5)(+) and Fe(2)Cl(4)(+) cations from iron(III) chloride vapor. The combination of the experimental results allows an evaluation of some of the thermochemical properties of the dinuclear Fe(2)Cl(n)()(+) cations: e.g., Delta(f)H(Fe(2)Cl(+)) = 232 +/- 15 kcal/mol, Delta(f)H(Fe(2)Cl(2)(+)) = 167 +/- 4 kcal/mol, Delta(f)H(Fe(2)Cl(3)(+)) = 139 +/- 4 kcal/mol, Delta(f)H(Fe(2)Cl(4)(+)) = 113 +/- 4 kcal/mol, Delta(f)H(Fe(2)Cl(5)(+)) = 79 +/- 5 kcal/mol, and Delta(f)H(Fe(2)Cl(6)(+)) = 93 +/- 2 kcal/mol. The analysis of the data suggests that structural effects are more important than the formal valency of iron as far as the Fe-Cl bond strengths in the Fe(2)Cl(n)()(+) ions are concerned.

Journal Article↗
PubMed2001

Platinum dioxide cation: easy to generate experimentally but difficult to describe theoretically.

A formal platinum(V) dioxide cation [Pt,O2](+) can be generated in the gas phase by successive oxidation of Pt(+) with N2O. The ion's reactivity is in keeping with the dioxide structure OPtO(+), rather than with [Pt,O2](+) isomers having intact O-O bonds, e.g., the dioxygen complex Pt(O2)(+) and peroxo species PtOO(+). Inter alia due to the high ionization energy of the neutral counterpart (11.2 eV), the [Pt,O2](+) cation is a rather aggressive reagent toward oxidizable neutrals. [Pt,O2](+) is even capable of activating inert substrates such as H2, CO, and CH4. Further, a sequence for the catalytic conversion CO + N(2)O --> CO2 + N2 is described with a turnover number of >100 for the catalytically active species PtOn(+) (n = 0-2). As a consequence of the high reactivity, however, the observed selectivities with most substrates are rather poor. For example, the reaction of PtO2(+) with ethane gives rise to 10 different product channels. In an attempt to analyze the structural features and different minima of the [Pt,O2](+) system, extensive ab initio studies are performed. While correlated ab initio methods describe the system reasonably well, density functional theory turns out to be much less accurate in terms of both structural and energetic descriptions.

Journal Article↗
PubMed2001

The importance of dihydrogen complexes HnGe(H2)+ (n=0,1) to the chemistry of cationic germanium hydrides: advanced theoretical and mass spectrometric analysis.

Investigations of [Ge,Hn]-/0/- (n = 2,3) have been performed using a four-sector mass spectrometer. The results reveal that the complexes HnGe(H2)+ (n = 0,1) play an important role in the unimolecular dissociation of the metastable cations. Theoretical calculations support the experimental observations in most instances, and the established view that the global minimum of [Ge,H2]+ is an inserted structure may need reexamination; CCSD(T,full)/cc-pVTZ//CCSD(T)/6-311 ++ G(d,p) and B3LYP/cc-pVTZ studies of three low-lying cation states (2A1 HGeH+, 2B2 Ge(H2)+ and 2B1 Ge(H2)+) indicate a very small energy difference (ca. 4 kcal mol(-1)) between 2A1 HGeH+ and 2B2 Ge(H2)+; B3LYP favours the ion-molecule complex, whereas coupled-cluster calculations favour the inserted structure for the global minimum. Single-point multireference (MR) averaged coupled-pair functional and MR-configuration interaction calculations give conflicting results regarding the global minimum. We also present theoretical evidence indicating that the orbital-crossing point implicated in the spin-allowed metastable dissociation HGeH+* --> Ge(H2)+* --> Ge+ + H2 lies above the H-loss asymptote. Thus, a quantum-mechanical tunneling mechanism is invoked to explain the preponderance of the H2-loss signal for the metastable ion.

Journal Article↗
PubMed2000

Ion chemistry of anti-o,o dibenzene.

The ion chemistry of anti-o,o'-dibenzene (1) was examined in the gaseous and the condensed phase. From a series of comparative ion cyclotron resonance (ICR) mass spectrometry experiments which involved the interaction of Cu+ with 1, benzene, or mixtures of both, it was demonstrated that 1 can be brought into the gas phase as an intact molecule under the experimental conditions employed. The molecular ions, formally 1*+ and 1*- , were investigated with a four-sector mass spectrometer in metastable-ion decay, collisional activation, charge reversal, and neutralization-reionization experiments. Surprisingly, the expected retrocyclization to yield two benzene molecules was not dominant for the long-lived molecular ions; however, other fragmentations, such as methyl and hydrogen losses, prevailed. In contrast, matrix ionization of 1 in freon (77 K) by gamma-radiation or in argon (12 K) by X-irradiation leads to quantitative retrocyclization to the cationic dimer of benzene, 2*+. Theoretical modeling of the potential-energy surface for the retrocyclization shows that only a small, if any, activation barrier is to be expected for this process. In another series of experiments, metal complexes of 1 were investigated. 1/Cr+ was formed in the ion source and examined by metastable ion decay and collisional activation experiments, which revealed predominant losses of neutral benzene. Nevertheless, comparison with the bis-ligated [(C6H6)2Cr]+ complex provided evidence for the existence of an intact 1/Cr+ under these experimental conditions. No evidence for the existence of 1/Fe+ was obtained, which suggests that iron mediates the rapid retrocyclization of 1/Fe+ into the bis-ligated benzene complex [(C6H6)2Fe]+.

Benzene Derivatives↗
PubMed2000

A mechanistic study of the FeO+-mediated decomposition pathways of phenol, anisol, and their thio analogues.

The gas-phase oxidations of phenol, anisol, thiophenol, and thioanisol by 'bare' FeO+ are examined by using Fourier transform-ion cyclotron resonance (FT-ICR) and tandem mass-spectrometry. Reaction mechanisms are derived on the basis of isotope-labeling experiments, MS/MS studies, and comparison with structural isomers, that is ions formed by independent routes. The chemistry of all substrates is determined by the functional groups, whereas reactions typical of unsubstituted benzene with FeO+ are suppressed. For phenol and thiophenol, four-membered metallacycles are obtained concomitant with a regioselective loss of water, which involves the O atom from the FeO+ entity and hydrogen atoms originating from the functional group and from the ortho position of the ring. C-H bond cleavage of the methoxy group (kH/kD = 2.0) is rate-contributing for the degradation of metastable anisol/FeO+, which is featured by highly regioselective losses of H2O, HCO, H2CO, and [C,H2,O2]. In the oxidation of thioanisol, two different C-H bond activation mechanisms are operating, resulting in the elimination of [Fe,H,O,S] concomitant with the formation of the benzyl cation (kH/kD = 4.7), and loss of water (kH/kD = 2.5). The reactions of independently generated, formal S- and C-oxidation intermediates of thioanisol indicate the occurrence of extensive structural isomerizations prior to dissociation. For anisol and thioanisol, analogies and differences between oxidation reactions catalyzed by the enzyme cytochrome P-450 in the condensed phase and those observed for the gas-phase model FeO+ are discussed.

Deuterium↗
PubMed2000

Towards Detection of a Long-lived Protonated Metal Cation: Generation of GeH(2+) Using High-Energy Collisions This research was supported by the Deutsche Forschungsgemeinschaft, the Volkswagen-Stiftung, and the Fonds der Chemischen Industrie. The Konrad-Zuse-Zentrum, Berlin, is acknowledged for generous allocation of computer time. R.S. is grateful to the Deutscher Akademischer Austauschdienst (DAAD) for financial support, and thanks Dr. K. V. Raghavan, Director of the Indian Institute of Chemical Technology, for his encouragement and assistance.

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Journal Article↗
PubMed2000

Two-state reactivity as a new concept in organometallic chemistry.

It is proposed that spin-crossing effects can dramatically affect reaction mechanisms, rate constants, branching ratios, and temperature behaviors of organometallic transformations. This phenomenon is termed two-state reactivity (TSR) and involves participation of spin inversion in the rate-determining step. While the present analysis is based on studies of transition metals under idealized conditions, several recent reports imply that TSR is by no means confined to the gas phase. In fact, participation of more than a single spin surface in the reaction pathways is proposed as a key feature in organometallic chemistry.

Organometallic Compounds↗
PubMed1999

Apolipoprotein E (ApoE), a Bmp-2 (bone morphogenetic protein) upregulated gene in mesenchymal progenitors (C3H10T1/2), is highly expressed in murine embryonic development.

Apolipoprotein E (ApoE) was identified as upregulated by Bmp-2 (bone morphogenetic protein-2) in the murine mesenchymal progenitor cell line C3H10T1/2 by a subtractive cloning strategy. Expression of recombinant Bmps in mesenchymal C3H10T1/2 progenitors results in the differentiation into the osteogenic, the chondrogenic, and the adipogenic lineage. In addition, ApoE is also expressed in primary osteoblasts isolated from murine calvariae late in the in vitro osteoblast developmental sequence. To infer possible roles of ApoE in organogenesis and tissue differentiation, ApoE expression during mouse embryonic development was analyzed in murine midgestation and late embryonic development by in situ hybridization. ApoE is highly expressed at many sites of organ development (liver, brain, heart, eye, lung), probably in a subset of neural crest cells and ectodermal derivatives suggestive for important functions of ApoE during embryonic differentiation and organ development.

Animals↗
PubMed1999

Developmental expression analysis of murine autotaxin (ATX).

The murine homologue of the human motility-stimulating protein autotaxin (ATX) was identified as a BMP2 upregulated gene by subtractive cloning from mesenchymal progenitors C3H10T1/2 (Bächner, D., Ahrens, M., Betat, N., Schröder, D., Hoffmann. A., Lauber, J., Steinert, P., Flohe, L., Gross, G., 1998. Bmp-2 downstream targets in mesenchymal development identified by subtractive cloning from recombinant mesenchymal progenitors (C3H10T1/2). Dev. Dyn. 213, 398-411). ATX mRNA transcription is induced during BMP2 mediated osteo-/chondrogenic differentiation in vitro several orders of magnitude. To delineate a potential role for ATX in osteo-/chondrogenic development, its expression pattern during murine embryogenesis was examined in comparison with Col1a1 and Col2a1, a marker either of osteoblast, odontoblast and tendon or of chondrocyte development, respectively. Localization of murine ATX was first observed in the floor plate of the neural tube at day 9.5 of mouse embryonic development. Later, enhanced ATX expression levels were observed in proliferating subepithelial mesenchyme, during osteo-/chondrogenic and tooth development, in choroid plexus epithelium, in late kidney development, and in smooth muscles of the ductus deferens and the bladder.

Animals↗
PubMed1998

Bmp-2 downstream targets in mesenchymal development identified by subtractive cloning from recombinant mesenchymal progenitors (C3H10T1/2).

ABmp-dependent in vitro model was used to identify cDNAs during the manifestation of mesenchymal lineages. This model involves the recombinant expression of Bmps (Bmp-2, Bmp-4-7) in murine mesenchymal C3H10T1/2 progenitors, which leads to the differentiation into three lineages: the osteogenic, the chondrogenic and the adipogenic lineage, albeit in varying efficiencies. By subtractive cloning, 21 Bmp-2-regulated cDNAs from C3H10T1/2 mesenchymal progenitors were identified; 20 were related to known sequences and 1 was not. During mouse embryonic development, many of these cDNAs are expressed in chondrogenic, osteogenic, and in adipogenic tissues. Novel findings include a G0/G1 switch gene (G0S2), which was demonstrated to be predominantly expressed in adipose tissue during late murine embryonic development. Furthermore, the membrane-standing glycoprotein autotaxin (ATX) is expressed, at precartilage condensations, joint regions, and during tooth development. An as yet undescribed cDNA, 29A, which encodes a putative secreted factor, is expressed in developing osteo-/chondrogenic tissues of vertebrae, ribs, tooth, and the limb bud. C3H10T1/2-progenitors, therefore, may serve as a legitimate model for the investigation of the Bmp-mediated events during mesenchymal differentiation.

Amino Acid Sequence↗
PubMed1998

Standard calculation of ethanol elimination rate is not sufficient to provide ethanol substitution therapy in the postoperative course of alcohol-dependent patients.

OBJECTIVE: Alcohol withdrawal syndrome (AWS) is a severe complication during postoperative treatment of alcohol-dependent patients. Besides the use of clomethiazole, clonidine, and benzodiazepines, there is another possible way to prevent AWS by deliberate administration of ethanol. The appropriate dosage of ethanol has not been known up to now and it could be defined according to the average ethanol elimination rate (EER) which, from forensic analysis, is known to be 15 mg/dl per h in a normal population. However, it is questionable whether these data are suitable for the calculation of the correct dosage in alcohol-dependent patients. DESIGN: Preliminary retrospective descriptive study. SETTING: Intensive care unit of a university teaching hospital. PATIENTS: 11 alcohol-dependent patients (9 males, 2 females, mean age 50.8 years, range 33 to 60 years). INTERVENTIONS: Ethanol substitution (ES) by parenteral application. MEASUREMENTS AND RESULTS: Ethanol kinetics were evaluated by repeated measurement of the blood ethanol concentration (BEC) over a period of at least 6 h parallel to the administration of ethanol. The average EER was found to be 28 mg/dl per h with a standard deviation of 11 mg/ dl per h. The minimum value was 18 mg/dl per h and the maximum 50 mg/dl per h. These EERs were significantly higher than the EERs known from forensic analysis. AWS was prevented in all 11 patients. CONCLUSIONS: Close control of BEC and precise adjustment of ethanol administration are necessary prerequisites for ES. The standard EER is not sufficient to define the appropriate ethanol dosage due to enormous variations in the ethanol metabolism of alcohol-dependent patients.

Adult↗
PubMed1998

A high risk phenotype of hypertrophic cardiomyopathy associated with a compound genotype of two mutated beta-myosin heavy chain genes.

Hypertrophic cardiomyopathy (HCM) is a genetically and clinically heterogeneous myocardial disease that is in most cases familial and transmitted in a dominant fashion. The most frequently affected gene codes for the cardiac (ventricular) beta-myosin heavy chain. We have investigated the genetic cause of an isolated case of HCM, which was marked by an extremely severe phenotype and a very early age of onset. HCM is normally not a disease of small children. The proband was a boy who had suffered cardiac arrest at the age of 6.5 years (resuscitation by cardioconversion). Upon screening of the beta-myosin heavy chain gene as a candidate, two missense mutations, one in exon 19 (Arg719Trp) and a second in exon 12 (Met349Thr), were identified. The Arg719Trp mutation was de novo, as it was not found in the parents. In contrast, the Met349Thr mutation was inherited through the maternal grandmother. Six family members were carriers of this mutation but only the proband was clinically affected. Segregation and molecular analysis allowed us to assign the Met349Thr mutation to the maternal and the Arg719Trp de novo mutation to the paternal beta-myosin allele. Thus, the patient has no normal myosin. We interpret these findings in terms of compound heterozygosity of a dominant (Arg719Trp) and a recessive (Met349Thr) mutation. Whereas a single mutated Arg719Trp allele would be sufficient to cause HCM, the concurrent Met349Thr mutation alone does not apparently induce the disease. Nevertheless, it conceivably contributes to the particularly severe phenotype.

Age of Onset↗
PubMed1998

Sustained decrease of peripheral lymphocytes after allogeneic blood stem cell aphereses.

48 healthy donors underwent peripheral blood stem cell (PBSC) apheresis for allogeneic transplantation beginning on day 4 of G-CSF (2 x 5 microg/kg) mobilization. In one to four (median two) large-volume mononuclear cell aphereses, a median of 55.9 x 10(9) of lymphocytes (range 21.0-109.2 x 10[9]) were collected, an amount comparable to lymphocyte numbers removed by therapeutic lymphaphereses in autoimmune diseases. Mean peripheral lymphocyte counts decreased from premobilization values of 2.31 x 10(9)/l to 1.31 x 10(9)/l at a median of 34 d (1 month) and 1.53 x 10(9)/l at a median of 327 d (11 months). The decrease in peripheral lymphocyte counts was significantly correlated with the number of lymphocytes removed and the number of aphereses. Neutrophil and platelet counts returned to normal values after 1 month whereas monocyte counts and haemoglobin concentrations were significantly decreased at 1 month but not at 11 months.

Female↗