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Biomedical subjects

Thomas Müller

Publications and source records attributed to Thomas Müller.

At least 19 recordsLinked to original sources
PubMed2003

Motor impairment influences Farnsworth-Munsell 100 Hue test error scores in Parkinson's disease patients.

Farnsworth-Munsell 100 Hue test (FMT) error scores and peg insertion abilities significantly differ between Parkinson's disease (PD) patients and controls. Both tasks ask for performance of voluntary movements. The objective of this study was to demonstrate a relation between FMT error scores and peg insertion outcomes. We successively performed both tasks in 28 previously untreated PD patients. The FMT error score was significantly (p=0.016) lower in patients with better peg insertion outcome. A significant (Spearman R=0.47, p=0.012) correlation between peg insertion results and the FMT error scores appeared. Motor impairment influences FMT error scores in PD patients.

Adult↗
PubMed2003

Serum lipid pattern unifies following renal transplantation in children.

Hyperlipidemia is a common problem in solid organ transplant recipients. In this study we evaluated the role of pre-transplant renal replacement therapy on early and late changes of serum lipid levels in children following renal transplantation. In 46 children with chronic renal failure (median age 10.3 years) and 12 children with heart failure (median age 5.0 years), cholesterol and triglycerides were measured before and during follow-up after transplantation. Children with renal failure had significantly higher serum lipids than controls ( n=34, median age 9.2 years) and patients with heart failure. Pre transplantation, cholesterol and triglycerides were significantly lower in the hemodialysis than in the peritoneal dialysis population, whereas conservatively treated children had intermediate levels. After transplantation, serum cholesterol converged towards a mean level of 208 mg/dl and triglyceride levels converged towards a uniform level of 195 mg/dl at 9 months post transplant. The ratio of cholesterol/high-density lipoprotein significantly decreased from 4.7 to 3.8. The pattern of "post-transplant hyperlipidemia" was similar in both renal and cardiac allograft recipients. Hence, the early post-transplant changes of serum lipid pattern are markedly dependent on the mode of pre-transplant renal replacement therapy. Later, serum lipid levels were no longer influenced by prior renal replacement therapy and showed a new pattern of "post-transplant hyperlipidemia" in all children.

Child↗
PubMed2003

Efficacy and safety of repeated intrathecal triamcinolone acetonide application in progressive multiple sclerosis patients.

Available immunomodulatory and conventional steroid treatment options for patients with progressive multiple sclerosis (MS) only provide limited symptomatic benefit. We performed an open trial on the short-term and long-term efficacy and safety of repeated intrathecal application of the sustained release steroid triamcinolone acetonide (TCA) in 36 progressive MS patients. Six TCA administrations, performed every third day, reduced the EDSS score (initial: 5.6+/-0.93 [mean+/-S.D.]; end: 4.9+/-1.0; p<0.001) and increased the walking distance (WD) (initial: 294+/-314 m; end: 604+/-540 m; p<0.001). Twenty MS patients continued intrathecal TCA treatment with one TCA injection performed with a variable frequency ranging from 6 to 12 weeks. Both EDSS and walking distance remained stable in these patients until the end of the follow-up investigation period. No serious side effects occurred. We conclude that repeated intrathecal TCA injection provides substantial benefit for progressive MS patients with predominantly spinal symptoms.

Adult↗
PubMed2003

Bis[bis(trimethylsilyl)amino]silylene, an unstable divalent silicon compound.

The title compound, [(Me3Si)2N]2Si: (1), was prepared by the reduction of [(Me3Si)2N]2SiBr2 (2) with potassium graphite at -78 degrees C. Unlike the corresponding germanium and tin compounds, 1 is unstable, but it can be studied in solution at low temperatures. The 29Si NMR chemical shift of 1 measured at -20 degrees C was 223.9 ppm, in good agreement with a value obtained from model calculations of 233 ppm. Reaction of solutions of 1 with methanol or phenol gave the trapping products expected for the silylene, [(Me3Si)2N]2Si(H)OR (R = CH3, C6H5).

Journal Article↗
PubMed2003

Standardisation and establishment of a rabies ELISA test in European laboratories for assessing the efficacy of oral fox vaccination campaigns.

A simple and rapid enzyme linked immunosorbent assay (ELISA) to detect rabies antibodies in field fox sera has been standardised and established in several European laboratories. The same panels of 100 coded sera were investigated by four laboratories using this ELISA assay and reference serum neutralisation techniques (fluorescent antibody virus neutralisation (FAVN) test and rapid fluorescent focus inhibition test (RFFIT)). This indirect ELISA technique is highly correlated with conventional seroneutralisation test on cell culture. Results obtained with this ELISA test provide an almost perfect agreement between laboratories while the agreement of FAVN test and RFFIT results is substantial and very satisfactory. In view of this study, this simple and rapid ELISA test is a suitable tool for evaluating the sero-conversion rate in fox populations following oral rabies vaccination campaigns in European countries.

Administration, Oral↗
PubMed2003

beta-Catenin signals regulate cell growth and the balance between progenitor cell expansion and differentiation in the nervous system.

beta-Catenin is an essential component of the canonical Wnt signaling system that controls decisive steps in development. We employed here two conditional beta-catenin mutant alleles to alter beta-catenin signaling in the central nervous system of mice: one allele to ablate beta-catenin and the second allele to express a constitutively active beta-catenin. The tissue mass of the spinal cord and brain is reduced after ablation of beta-catenin, and the neuronal precursor population is not maintained. In contrast, the spinal cord and brain of mice that express activated beta-catenin is much enlarged in mass, and the neuronal precursor population is increased in size. beta-Catenin signals are thus essential for the maintenance of proliferation of neuronal progenitors, controlling the size of the progenitor pool, and impinging on the decision of neuronal progenitors to proliferate or to differentiate.

Alleles↗
PubMed2003

A free, tricoordinate stannylium cation.

Tris(2,4,6-triisopropylphenyl)stannylium tetrakis(pentafluorophenyl)borate constitutes a free, tricoordinate tin cation according to its X-ray structure. There is no coordination between the cation and either solvent or anion, and there are no atoms at apical positions. DFT calculations confirm the structure and indicate that there is no agostic bonding between the ortho isopropyl methinyl hydrogens and the Sn atom. Calculation of the 119Sn chemical shift is in good agreement with the observed value.

Journal Article↗
PubMed2003

Coenzyme Q10 supplementation provides mild symptomatic benefit in patients with Parkinson's disease.

Features of Parkinson's disease (PD) include oxidative stress, nigral mitochondrial complex I deficiency and visual dysfunction, all of which are also associated with coenzyme Q(10) (CoQ(10)) deficiency. The objective of this monocenter, parallel group, placebo controlled, double-blind trial was to determine the symptomatic response of daily oral application of 360 mg CoQ(10) lasting 4 weeks on scored PD symptoms and visual function, measured with the Farnsworth-Munsell 100 Hue test (FMT), in 28 treated and stable PD patients. CoQ(10) supplementation provided a significant (P=0.01) mild symptomatic benefit on PD symptoms and a significantly (F((1,24))=8.48, P=0.008) better improvement of FMT performance compared with placebo. Our results indicate a moderate beneficial effect of oral CoQ(10) supplementation in PD patients.

Aged↗
PubMed2003

Apomorphine reduces BOLD signal in fMRI during voluntary movement in Parkinsonian patients.

Our group investigated modulatory effects of apomorphine on cerebral activation patterns during finger tapping movements in seven Parkinson's disease (PD) patients off medication. Cerebral activation was measured according to an established fMRI protocol. Apomorphine application disclosed a reduction of cerebral activation patterns to the contralateral precentral gyrus affecting both clinically affected and unaffected sides; tapping with the unaffected hand additionally revealed activation in the contralateral postcentral gyrus. These findings contradict those of similar functional imaging studies performed in PD to date, which variously found augmentation of cerebral activation patterns in Parkinsonian patients after dopaminergic stimulation. One conceivable explanation for our singular results would be preferred binding of apomorphine to presynaptic dopaminergic receptors, leading to inhibition of endogenous dopamine release and resultant diminished dopaminergic stimulation, reflected in diminished cerebral activation patterns. These findings warrant future consideration and further investigation of possible central inhibitory effects of dopaminergic therapy in functional imaging studies in PD.

Antiparkinson Agents↗
PubMed2003

Unique coordination of two C=C double bonds to an electron-deficient lead center.

Reaction of bis(cyclopentenemethyl)diethylplumbane (2) with trityl cation leads to the formation of the plumbyl cation bis(cyclopentenemethyl)plumbylium (1), in which the positively charged lead atom interacts with the two C=C double bonds of the cyclopentene ligands. The plumbyl cation 1 is characterized by NMR spectroscopy (delta((207)Pb)=807 ppm, delta((13)C(C=C))= 136.1 ppm, (1)J(Pb,C=C)=14.4 Hz) and X-ray crystallography. The structure of 1 reveals a distorted trigonal-bipyramidal coordination sphere for the lead atom with a unique coordination of two C=C double bonds in apical positions. According to quantum-mechanical calculations (MP2/6-311G(d,p) (C, H), SDD (Pb)//MP2/6-31G(d), SDD (Pb)) this interaction stabilizes 1 by 28.3 kcal mol(-1) relative to the tricoordinated plumbylium ion 10. An "atoms in molecules" (AIM) analysis indicates a pi-type interaction between the lead atom and the C=C double bonds, reminiscent of that in the 2-norbornyl cation.

Journal Article↗
PubMed2003

Intravenous amantadine sulphate application improves the performance of complex but not simple motor tasks in patients with Parkinson's disease.

Intravenous application of amantadine sulphate induces a rapid improvement of motor symptoms in Parkinson's disease (PD), but there are no trials on the efficacy of this compound on bradykinesia, rigidity and tremor in detail in combination with standardized instrumental measurement of tapping and peg insertion abilities. We treated 31 stable non fluctuating PD patients with amantadine, scored motor symptoms of both arms and performed peg insertion and tapping under cued conditions before and after 3 days. Motor symptoms and peg insertion significantly improved in contrast to tapping. Tapping asks for repetitive performance of simple standardized movements, therefore it needs low cognitive efforts. Since peg insertion depends on more complex movements and thus more dopamine dependent cognitive processes, it improved after application of the indirect dopaminomimetic substance amantadine.

Aged↗
PubMed2003

Norbornyl cations of group 14 elements.

Norbornyl cations of the group 14 elements Si --> Pb have been synthesized from substituted 3-cyclopentenemethyl precursors by intramolecular addition of transient cations to the C=C double bond of the 3-cyclopentenemethyl substituent (pi-route to norbornyl cations). The norbornyl cations 4a (E = Si, R = Me), 4e (E = Si, R = Et), 4f (E = Si, R = Bu), 4g (E = Ge, R = Bu), 4h (E = Sn, R = Bu), and 4i (E = Pb, R = Et) have been identified by their characteristic NMR chemical shifts (4a,e,f, delta((29)Si) = 80-87, delta((13)C)(CH=) = 149.6-150.6; 4g, delta((13)C)(CH=) = 144.8; 4h, delta((119)Sn) = 334, delta((13)C)(CH=) = 141.5; 4i, delta((207)Pb) = 1049, delta((13)C)(CH=) = 138). The significant deshielding of the vinylic carbon atoms (Deltadelta((13)C)) relative to those of the precursor (Deltadelta((13)C) = 19.3-20.3 (4a,e,f), Deltadelta((13)C) = 14.6 (4g), Deltadelta((13)C) = 11.1 (4h), Deltadelta((13)C) approximately 8 (4i)) and the small J coupling constants between the element and the remote vinyl carbons in the case of 4h and 4i (J(CSn) = 26 Hz, J(CPb) = 16 Hz) give experimental evidence for the intramolecular interaction and the charge transfer between the positively charged element and the remote C=C double bond. The experimental results are supported by quantum mechanical calculations of structures, energies, and magnetic properties for the norbornyl cations 4a,b (E = Ge, R = Me), 4c (E = Sn, R = Me), 4d (E = Pb, R = Me), and 4e,f at the GIAO/B3LYP/6-311G(3d,p)//MP2/6-311G(d,p) (Si, Ge, C, H), SDD (Sn, Pb) level of theory. The calculated (29)Si NMR chemical shifts for the silanorbornyl cations 4a,e,f (delta((29)Si) = 77-93) agree well with experiment, and the calculated structures of the cations 4a-f reveal their bridged norbornyl cation nature and suggest also for the experimentally observed species 4a,e-i a formally 3 + 1 coordination for the element atom with the extra coordination provided by the C=C double bond. This places five carbon atoms in the close vicinity of the positively charged element atom. The group 14 element norbornyl cations 4a,e-i exhibit only negligible interactions with the aromatic solvent, and they are, depending on the nature of the element group, stable at room temperature in aromatic solvents for periods ranging from a few hours to days. In acetonitrile solution, the intramolecular interaction in the norbornyl cations 4a,e-h breaks down and nitrilium ions with the element in a tetrahedral environment are formed. In contrast, reaction of acetonitrile with the plumbyl cation 4i forms an acetonitrile complex, 10i, in which the norbornyl cation structure is preserved. The X-ray structure of 10i reveals a trigonal bipyramidal environment for the lead atom with the C=C double bond of the cyclopentenemethyl ligand and the nitrogen atom of the acetonitrile molecule in apical positions. Density functional calculations at the B3LYP/6-311G(2d,p)//(B3LYP/6-31G(d) (C, H), SDD (Si, Ge, Sn, Pb)) + DeltaZPVE level indicate that the thermodynamic stability of the group 14 norbornyl cations increases from Si to Pb. This results in a relative stabilization for the plumbanorbornyl cation 4d compared to tert-butyl cation of 52.7 kcal mol(-)(1). In contrast, the intramolecular stabilization energy E(A) of the norbornyl cations 4a-d decreases, suggesting reduced interaction between the C=C double bond and the electron-deficient element center in the plumbacation compared to the silacations. This points to a reduced electrophilicity of the plumbacation compared to its predecessors.

Journal Article↗
PubMed2003

A new subclass of the luteinizing hormone/chorionic gonadotropin receptor lacking exon 10 messenger RNA in the New World monkey (Platyrrhini) lineage.

The luteinizing hormone receptor (LHR) plays an essential role as a mediator of LH and CG action during embryonic sexual differentiation and in gametogenesis. In a hypogonadal male patient, we recently demonstrated that a genomic deletion of exon 10, located in the hinge region of the extracellular domain, results in discrimination of LH and hCG action. In the common marmoset (Calltithrix jacchus), exon 10 of the LHR is naturally missing at the mRNA level. In order to investigate whether this is an isolated species-specific phenomenon, we performed a phylogenetic screening, searching for the presence of LHR exon 10 mRNA in a number of primate species representative for the major lineages of primate evolution. The expressed LHR region encompassing exon 10 was amplified from testicular tissue by RT-PCR, cloned, and sequenced. In addition, we performed Southern blot analysis of the LHR of selected New World and Old World primates. The results revealed that exon 10 mRNA is lacking in the complete New World monkey (Platyrrhini) lineage but is present in both more primitive and more advanced primates. However, exon 10 seems to be present at the genomic level, arguing for a splicing failure possibly due to a genomic mutation or the lack of appropriate splicing factors. Considering that, in the human, LH is far less active than hCG on the LHR lacking exon 10, we addressed the question whether the existence of such a receptor has any consequences on the dual hormone LH/CG system present in Platyrrhini. Using primers specific for the known marmoset CG beta cDNA, we amplified the CG beta subunit cDNA from male common marmoset pituitaries by RT-PCR, while LH beta could not be amplified, suggesting a possible physiological role of pituitary CG in this species. In conclusion, we demonstrated for the first time that the LH mRNA without exon10 is the natural wild-type LHR in the Platyrrhini lineage. We propose that this LHR represents a new subclass of receptors that should be named LHR type II. In addition, the high expression of CG beta in the marmoset pituitary suggests a physiological role of CG in the reproductive function of these primates beyond pregnancy.

Amino Acid Sequence↗
PubMed2003

Activated beta-catenin induces osteoblast differentiation of C3H10T1/2 cells and participates in BMP2 mediated signal transduction.

Wnt glycoproteins are important regulators of cellular differentiation and embryonic development. Some Wnt proteins induce stabilization of beta-catenin which cooperatively regulates gene expression with LEF/Tcf transcription factors. Here we demonstrate a direct role for beta-catenin signaling in osteoblast differentiation and in BMP2-mediated signal transduction. Similar to treatment with BMP-2 protein, ectopic expression of stabilized beta-catenin in C3H10T1/2 cells or activation of endogenous beta-catenin signaling with LiCl induces expression of alkaline phosphatase mRNA and protein, a defined marker of early osteoblast differentiation. Unlike BMP2 protein, stabilized beta-catenin does not induce osteocalcin gene expression, a marker of late osteoblast differentiation. BMP2-induced differentiation also leads to activation of endogenous beta-catenin signaling thus implicating beta-catenin in early steps of BMP2-mediated osteoblast differentiation. Effects of beta-catenin and BMP2 on C3H10T1/2 differentiation are not completely overlapping, implying that some aspects of BMP2-induced differentiation may be mediated by beta-catenin signaling and that beta-catenin can also participate in non-BMP2-dependent differentiation processes.

Alkaline Phosphatase↗
PubMed2003

Acquisition of neuronal and glial markers by neural crest-derived cells in the mouse intestine.

Enteric neurons and glia arise from the neural crest. The phenotype of crest-derived cells was examined as they differentiated into neurons or glia in the mouse small and large intestine. Previous studies have shown that undifferentiated enteric crest-derived cells are Phox2b(+)/Ret(+)/p75(+)/Sox10(+), and at embryonic day (E) 10.5, about 10-15% of the crest-derived cells in the small intestine have started to differentiate into neurons. In the current study, by E12.5 and E14.5, about 25% and 47%, respectively, of Phox2b(+) cells in the small intestine were immunoreactive to the pan-neuronal protein, ubitquitin hydrolase (PGP9.5), and the percentage did not change dramatically from E14.5 onward. The differentiation of crest-derived cells into neurons in the colon lagged behind that in the small intestine by several days. Differentiating enteric neurons showed high Ret, low p75, and undetectable Sox10 immunostaining. Glial precursors were identified by the presence of brain-specific fatty acid binding protein (B-FABP) and detected first in the fore- and rostral midgut at E11.5. Glial precursors appeared to be B-FABP(+)/Sox10(+)/p75(+) but showed low Ret immunostaining. S100b was not detected until E14.5. Adult glial cells were B-FABP(+)/Sox10(+)/p75(+)/S100b(+). A nucleic acid stain (to identify all ganglion cells) was combined with immunostaining for PGP9.5 and S100b to detect neurons and glial cells, respectively, in the postnatal intestine. At postnatal day 0, fewer than 5% and 10% of cells in myenteric ganglia of the small and large intestine, respectively, were neither PGP9.5(+) nor S100b(+). Because some classes of neurons are not present in significant numbers until after birth, the expression of PGP9.5 by developing enteric neurons appeared to precede the expression of neuron type-specific markers.

Animals↗
PubMed2003

The canine copper toxicosis gene MURR1 does not cause non-Wilsonian hepatic copper toxicosis.

BACKGROUND: Non-Wilsonian hepatic copper toxicosis includes Indian childhood cirrhosis (ICC), endemic Tyrolean infantile cirrhosis (ETIC) and the non-Indian disease known as idiopathic copper toxicosis (ICT). These entities resemble the hepatic copper overload observed in livers of Bedlington terriers with respect to their clinical presentation and biochemical and histological findings. We recently cloned the gene causing copper toxicosis in Bedlington terriers, MURR1, as well as the orthologous human gene on chromosome 2p13-p16. AIM: To study the human orthologue of the canine copper toxicosis gene as a candidate gene for ICC, ETIC, and ICT. METHODS: We sequenced the exons and the intron-exon boundaries of the human MURR1 gene in 12 patients with classical ICC, one patient with ETIC, and 10 patients with ICT to see whether these patients display any mutations in the human orthologue of the canine copper toxicosis gene. RESULTS: No mutations in the MURR1 gene, including the intron-exon boundaries, were identified in a total of 23 patients with non-Wilsonian hepatic copper toxicosis. CONCLUSIONS: Our results demonstrate that copper toxicosis in Bedlington terriers is not an animal model for the non-Wilsonian hepatic copper toxicosis described in this study.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Evidence for genetic heterogeneity in lymphedema-cholestasis syndrome.

Lymphedema-cholestasis syndrome (LCS, Aagenaes syndrome) is the only known form of hereditary lymphedema associated with cholestasis. A locus, LCS1, has recently been mapped to chromosome 15q in a Norwegian kindred. In a consanguine Serbian Romani family with a neonate who had a combination of lymphedema and cholestasis with features atypical for Norwegian LCS, haplotype and linkage analysis of markers spanning the LCS1 region argue that a second LCS locus may exist. The infant may represent an instance of a previously undescribed lymphedema-cholestasis syndrome.

Cholestasis↗