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Biomedical subjects

A Müller

Publications and source records attributed to A Müller.

At least 91 records · Page 5Linked to original sources
PubMed2002

Olfactory function in idiopathic Parkinson's disease (IPD): results from cross-sectional studies in IPD patients and long-term follow-up of de-novo IPD patients.

Olfactory loss is a prominent symptom in idiopathic Parkinson's disease (IPD). Experiment 1 re-investigated the diagnostic value of psychophysical testing in the differentiation between idiopathic Parkinson disease (IPD) from non-IPD; 50 consecutive PS patients participated. In Experiment 2 five de-novo patients received 3 olfactory tests spread over a period of approximately one year. Nineteen IPD patients were anosmic, and 18 were hyposmic. All but one patient with MSA and PSP had mild/moderate hyposmia. Normosmia was found in CBD/misdiagnosed PS/psychogenic movement disorder. In Experiment 2, one of the de-novo patients was normosmic, 3 hyposmic, and 1 anosmic. Follow up investigations indicated decreased olfactory function in 3 patients while it improved in one. The normosmic patient retained olfactory abilities. This patient failed to respond to pharmacological treatment. In summary, olfactory tests differentiate IPD from non-IPD. Furthermore, tests of olfactory function may also be of interest in investigations related to treatment of PS.

Adult↗
PubMed2002

[Comparison of secondary and tertiary cleft jaw osteoplasty. 20 year analysis].

BACKGROUND: The aim of secondary cleft osteoplasty is to provide alveolar bone for the complete eruption of the canine and sometimes of the lateral incisor to the occlusal plane and, thus, preservation of a continuous dental arch. This concept has not changed during the last 20 years in our clinic, providing an opportunity for an analysis of a homogeneous group of cleft patients. This group of patients was compared with a similar group of tertiary osteoplasties, performed during the same time span in our clinic. MATERIAL AND METHODS: From 1980 to 1999, 376 cleft osteoplasties were performed in 295 patients, 264 of whom (136 secondary and 128 tertiary osteoplasties) were available for continuous prospective follow-up. Special emphasis was put on preoperative orthodontic treatment with removal of crossbites, oral hygiene, and meticulous disinfection. Autogenous cancellous iliac bone was used exclusively. RESULTS: The postoperative height of the interalveolar septum (Abyholm classes) was I (1/1, 69.4%/45.8%), II (> 3/4, 28.2%/41.7%), III (< 3/4, 2.4%/10%), and IV (complete failure, 0%/2.5%) (secondary vs tertiary). Complications were infections (6.6% vs 14%), fistulae (0.7% vs 5.8%), and external root resorption (0% vs 7.4%). The lateral incisor was aligned into the arch in 55.5% vs 29.8% and the canine was in the correct position in 100% vs 83.6% (secondary vs tertiary). CONCLUSION: Secondary cleft osteoplasty was more advantageous than tertiary due to better preservation of the neighboring teeth.

Adolescent↗
PubMed2002

Overview of economic evaluation of positron-emission tomography.

Since the 1990s positron-emission tomography (PET) in Germany has been used increasingly in clinical diagnostics in the areas of oncology, cardiology, and neurology/ psychiatry. As the use of PET requires a complex and expensive infrastructure, analysis of the cost-effectiveness of PET compared to common diagnostic methods is becoming increasingly important. This contribution summarizes and discusses the results of a health technology assessment report on the cost-effectiveness of PET.

Journal Article↗
PubMed2002

Olfactory function in Parkinsonian syndromes.

The study aimed to compare olfactory function in idiopathic Parkinson's disease (IPD) and nonidiopathic Parkinson's syndrome (PS). At their first visit 50 PS patients (age 38-80 years) received testing for odor threshold, olfactory discrimination and identification. All patients underwent extensive neurological diagnostics including PET scans. Patients were followed up for 6-12 months. Most of IPD patients were functionally anosmic (n=19), the remaining IPD patients had severe/moderate hyposmia (n=18). PS patients diagnosed with multiple system atrophy had less severe olfactory deficits (7 hyposmia, 1 normosmia). With the exception of 1 hyposmic patient, other PS patients had no olfactory deficits (progressive supranuclear palsy, corticobasal degeneration, psychogenic PS, essential tremor). This study added to previous findings: (1) there was no major difference betwesen olfactory function in IPD subtypes; (2) all olfactory tests differentiated IPD from nonIPD. These data suggest that olfactory probes improve the diagnostic armamentarium in IPD.

Adult↗
PubMed2002

A method to assess biochemical activity of liver cells during clinical application of extracorporeal hybrid liver support.

Biochemical activity of a hybrid liver support system based on porcine liver cells was investigated in patients suffering from acute liver failure, coma stage III-IV Patient plasma was drawn systemically and after circulation through the bioreactor at four hour intervals. A method is used that takes into account the rate of plasma flow and the differences in plasma concentration systemically and after circulation through the liver support system to determine the net release or uptake of metabolites such as ammonia, urea and glucose. Urea release (mean 2.28+/-0.37 micromol/h/g cells) and ammonia uptake (mean 0.17+/-0.11 micromol/h/g cells) was seen during treatment, an active role of the system in glucose metabolism was observed. All patients were bridged successfully to liver transplantation.

Ammonia↗
PubMed2002

Retention of dopamine 2 receptor mRNA and absence of the protein in craniospinal and extracranial metastasis of a malignant prolactinoma: a case report.

OBJECTIVES: The case presented here describes the clinical evolution of a malignant prolactinoma with occurrence of intra- and extra-cranial metastases. In this case, the presence of dopamine 2 receptor (D2R) was studied at the mRNA and protein level, in order to understand the pathological background of the resistance to treatment with different dopamine agonists. DESIGN: Together with an extensive description of the clinical history of this case, a combination of in vitro and in vivo techniques was performed to provide the basis of the dopamine resistance developed in the course of the disease. METHOD: A comparison of the D2R was performed in specimens obtained at presentation of the disease compared with autoptic specimens derived from local invasion and metastasis using in situ hybridization and immunohistochemical techniques. RESULTS: Intact D2R mRNA was found in the primitive tumor and metastatic tissues, whereas protein for the same receptor was present only in the tissues derived from neurosurgical operations and not in the metastases obtained post-mortem. CONCLUSION: This is the first report of the absence of D2R protein despite the retention of the transcript in an advanced stage of a malignant prolactinoma. The findings of this single case suggest the hypothesis that postranscriptional mechanisms may contribute to the development of dopamine resistance in prolactinomas.

Brain Neoplasms↗
PubMed2002

[Pathology of vasculitis: differential diagnosis and selected disorders].

The morphological diagnosis of vasculitis is a challenge for the pathologist for many reasons. Primary systemic vasculitides are rare diseases (ann. incidence 4-5/100,000 according to the Vaskulitis-Register Schleswig-Holstein), pathognomonic histopathological findings are hard to obtain in many patients even with multiple biopsies, and the nomenclature of vasculitis has long been confusing and unequivocal. The Chapel-Hill Consensus Conference (1992) is credited with the establishment of clinico-pathological definitions for primary systemic vasculitides. For the discrimination of primary systemic vasculitis from secondary vasculitis as well as pseudovasculitic syndromes, correlation with clinical data is essential; it has been facilitated by the American College of Rheumatology (ACR) classification criteria (1990). Differential diagnostic schemes for vasculitis are based on the predominant type and size of the blood vessel involved, as well as the histopathological type of inflammation and the presence or absence of immune complex deposits. However, differential diagnostic problems remain: even with the clarified nomenclature of Chapel-Hill, considerable overlap still occurs. A clinical diagnosis of vasculitis is now often established in an earlier disease stadium, in part of the cases facilitated by ANCA testing; the pathologist may therefore at first be confronted with a more subtle or abortive morphology, while in the course of disease, histopathology is modulated by immunosuppressive therapy. A number of immunopathogenic mechanisms prevailing in vasculitis can be verified with immunohistochemical and molecular biological methods, although it is frequently not known how they are initiated and perpetuated. ANCA-associated vasculitides serve as a good example to demonstrate the central role of morphology, its potentials but also its limitations in the differential diagnosis of vasculitis.

Diagnosis, Differential↗
PubMed2001

Mimicking oxide surfaces: different types of defects and ligand coordination at well defined positions of a molybdenum oxide based nanocluster.

The mixed valence cluster anion of the compound (NH4)32[MoVI110MoV28O416H6(H2O)58(CH3CO2)6].xH2O 1 (x approximately 250), synthesized under one-pot conditions, contains well-defined different types of defects--missing groups compared to the complete parent (Mo154) type cluster with full D7d symmetry--and acetate ligand coordination; this proves that the giant-wheel type anion can be considered as an object with a variety of nanoscale structural features ("nanostructured landscape") allowing reactions at a variety of well defined centers.

Journal Article↗
PubMed2001

Hierarchic patterning: architectures beyond 'giant molecular wheels'.

Based on symmetry breaking steps under one-pot conditions, simple molybdenum oxide-based building blocks initially assemble to 'giant molecular wheels' in a fast process followed by further slower assembly processes leading stepwise to more complex mesoscopic architectures including spherical ones and finally to those with a size larger than 500 nm.

Journal Article↗
PubMed2001

Comparison of fat retainers in accelerated solvent extraction for the selective extraction of PCBs from fat-containing samples.

Five types of fat retainers were investigated for the lipid-free extraction of PCBs from fat-containing matrixes using accelerated solvent extraction: florisil, basic alumina, neutral alumina, acidic alumina, and sulfuric acid-impregnated silica. All of the fat retainers generated fat-free extracts when the fat/fat retainer ratio was 1:40. Sulfuric acid-impregnated silica and florisil were the only retainers that gave completely clear extracts, and the former was the only not to show any reaction when treated with sulfuric acid after the extraction. Using sulfuric acid-impregnated silica as fat retainer, on-line cleanup of fat-containing matrixes was possible, as demonstrated for naturally contaminated fish meal as well as certified cod liver oil (CRM 349).

Animals↗
PubMed2001

On-line clean-up of pressurized liquid extracts for the determination of polychlorinated biphenyls in feedingstuffs and food matrices using gas chromatography-mass spectrometry.

This paper describes a fast and simple pressurized liquid extraction method for the determination of polychlorinated biphenyls (PCBs) in feedingstuffs and food matrices. The method is based on a simultaneous extraction/clean-up step requiring a minimum of sample handling. The final analysis was performed with gas chromatography-mass spectrometry. Seven PCBs (28, 52, 101, 118, 138, 153 and 180) were analyzed, all of which are indicator congeners that, according to European legislation should be included in the analytical monitoring program. The extracted matrices were spiked feed for poultry and two certified reference materials naturally contaminated with PCBs (cod-liver oil and milk powder), which showed excellent conformity with certified data.

Animal Feed↗
PubMed2001

Engineering regulable Escherichia coli beta-galactosidases as biosensors for anti-HIV antibody detection in human sera.

The activity of engineered, peptide-displaying enzymes is modulated by binding to specific anti-peptide antibodies. This new concept of a quantitative antibody detection system allows test kits to be set up for fast diagnosis of infectious diseases. To develop a quick and homogeneous assay for the detection of human immunodeficiency virus (HIV) infection, we have explored two acceptor sites of the bacterial Escherichia coli beta-galactosidase for the accommodation of HIV antigenic peptides. Two overlapping epitopes (namely P1 and P2) from the gp41 envelope glycoprotein, contained in different sized peptides, were inserted in the vicinity of the enzyme active site to generate a set of hybrid, enzymatically active beta-galactosidases. Regulable enzymes of different responsiveness to monoclonal antibody binding were generated with both acceptor sites tested. These biosensors were also sensitive to immune sera from HIV-infected patients. Modeling data provide insight into the structural modifications in the vicinity of the active site induced by peptide insertion that strongly affect the responsiveness of the engineered proteins through different parameters of their catalytic properties.

Amino Acid Sequence↗
PubMed2001

The Fe-only nitrogenase from Rhodobacter capsulatus: identification of the cofactor, an unusual, high-nuclearity iron-sulfur cluster, by Fe K-edge EXAFS and 57Fe Mössbauer spectroscopy.

Samples of the dithionite-reduced FeFe protein (the dinitrogenase component of the Fe-only nitrogenase) from Rhodobacter capsulatus have been investigated by 57Fe Mössbauer spectroscopy and by Fe and Zn EXAFS as well as XANES spectroscopy. The analyses were performed on the basis of data known for the FeMo cofactor and the P cluster of Mo nitrogenases. The prominent Fourier transform peaks of the Fe K-edge spectrum are assigned to Fe-S and Fe-Fe interactions at distances of 2.29 A and 2.63 A, respectively. A significant contribution to the Fe EXAFS must be assigned to an Fe backscatterer shell at 3.68 A, which is an unprecedented feature of the trigonal prismatic arrangement of iron atoms found in the FeMo cofactor of nitrogenase MoFe protein crystal structures. Additional Fe...Fe interactions at 2.92 A and 4.05 A clearly indicate that the principal geometry of the P cluster is also conserved. Mössbauer spectra of 57Fe-enriched FeFe protein preparations were recorded at 77 K (20 mT) and 4.2 K (20 mT, 6.2 T), whereby the 4.2 K high-field spectrum clearly demonstrates that the cofactor of the Fe-only nitrogenase (FeFe cofactor) is diamagnetic in the dithionite-reduced ("as isolated") state. The evaluation of the 77 K spectrum is in agreement with the assumption that this cofactor contains eight Fe atoms. In the literature, several genetic and biochemical lines of evidence are presented pointing to a significant structural similarity of the FeFe, the FeMo and and the FeV cofactors. The data reported here provide the first spectroscopic evidence for a structural homology of the FeFe cofactor to the heterometal-containing cofactors, thus substantiating that the FeFe cofactor is the largest iron-sulfur cluster so far found in nature.

Ferredoxins↗
PubMed2001

IL-4 determines eicosanoid formation in dendritic cells by down-regulation of 5-lipoxygenase and up-regulation of 15-lipoxygenase 1 expression.

Dendritic cell (DC) differentiation from human CD34(+) hematopoietic progenitor cells (HPCs) can be triggered in vitro by a combination of cytokines consisting of stem cell factor, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha. The immune response regulatory cytokines, IL-4 and IL-13, promote DC maturation from HPCs, induce monocyte-DC transdifferentiation, and selectively up-regulate 15-lipoxygenase 1 (15-LO-1) in blood monocytes. To gain more insight into cytokine-regulated eicosanoid production in DCs we studied the effects of IL-4/IL-13 on LO expression during DC differentiation. In the absence of IL-4, DCs that had been generated from CD34(+) HPCs in response to stem cell factor/granulocyte-macrophage colonystimulating factor/tumor necrosis factor alpha expressed high levels of 5-LO and 5-LO activating protein. However, a small subpopulation of eosinophil peroxidase(+) (EOS-PX) cells significantly expressed 15-LO-1. Addition of IL-4 to differentiating DCs led to a marked and selective down-regulation of 5-LO but not of 5-LO activating protein in DCs and in EOS-PX(+) cells and, when added at the onset of DC differentiation, also prevented 5-LO up-regulation. Similar effects were observed during IL-4- or IL-13-dependent monocyte-DC transdifferentiation. Down-regulation of 5-LO was accompanied by up-regulation of 15-LO-1, yielding 15-LO-1(+) 5-LO-deficient DCs. However, transforming growth factor beta1 counteracted the IL-4-dependent inhibition of 5-LO but only minimally affected 15-LO-1 up-regulation. Thus, transforming growth factor beta1 plus IL-4 yielded large mature DCs that coexpress both LOs. Localization of 5-LO in the nucleus and of 15-LO-1 in the cytosol was maintained at all cytokine combinations in all DC phenotypes and in EOS-PX(+) cells. In the absence of IL-4, major eicosanoids of CD34(+)-derived DCs were 5S-hydroxyeicosatetraenoic acid (5S-HETE) and leukotriene B(4), whereas the major eicosanoids of IL-4-treated DCs were 15S-HETE and 5S-15S-diHETE. These actions of IL-4/IL-13 reveal a paradigm of eicosanoid formation consisting of the inhibition of one and the stimulation of another LO in a single leukocyte lineage.

Antigens, CD34↗