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T Maier

Publications and source records attributed to T Maier.

At least 19 recordsLinked to original sources
PubMed2003

[Development of delusion in view of Luhmann's systems theory].

The systems theory of Niklas Luhmann declares itself as a universal theory and therefore claims applicability to any social and psychic phenomenon.In spite of its high complexity, to many it seems too vague and nonspecific. The possible usefulness of this theory should be demonstrated on the example of the development of delusion, still a mysterious and unexplained phenomenon. Within the framework of Luhmann's systems theory, delusion can be considered a communication disorder and therefore a phenomenon within the social system. Both the autopoietic systems society and psyche are based on and processed by meaning but cannot communicate directly, and they are mutually nontransparent and unpredictable. Due to this fact, the interface between the two systems is a potential source of disturbances. Luhmann defines the distinction of information, message, and understanding as the crucial element to connect the social system with the psychic one. If the psychic system fails to recognize the message of an information correctly or is unable to negotiate between understanding and misunderstanding messages, it detaches itself from the social system to which it is normally closely connected. This detachment releases the possibility of unhindered autistic fulfillment of desires and uncontrolled fear. Due to the meaning-based autopoiesis of the psychic system,these released thoughts and emotions still appear in meaningfully condensed form as delusions.

Autistic Disorder↗
PubMed2001

Insect immune activation by apolipophorin III is correlated with the lipid-binding properties of this protein.

Apolipophorin III (apoLp-III) is an exchangeable insect apolipoprotein consisting of five amphipathic alpha-helices. The protein is able to open reversibly on associating with hydrophobic surfaces and plays a role both in lipid transport and induction of immune responses. Point mutations were introduced at positions 66 (N-->D) and/or 68 (K-->E) between helices 2 and 3, a region possibly serving as a hinge for the opening of the molecule when associating with lipids. The lipid-binding properties of the mutant proteins were analyzed and compared with their immune inducing activities. Structural properties of the proteins were studied by far UV circular dichroism spectroscopy and their abilities to form discoidal complexes of dimyristoyl phosphatidylcholine (DMPC) vesicles were investigated. In comparison to wild-type apoLp-III, apoLp-III(N66D/K68E), and apoLp-III(K68E) displayed significantly decreased lipid-binding abilities and immune stimulating activities, while these effects were less noticeable with apoLp-III(N66D). The secondary structure of the double mutant apoLp-III(N66D/K68E) was similar to that of wild-type apoLp-III. A noticeable reduction of alpha-helical content could be observed for the single mutants apoLp-III(N66D) and apoLp-III(K68E), which was accompanied by an increase in percentage amount of beta-turns. The stability of the secondary structure determined by heat denaturation was not affected by mutagenesis. Furthermore, the ability of all proteins to form discoidal complexes of equal size and shape in the presence of dimyristoyl phosphatidylcholine indicated that the mutagenesis did not affect the molecular architecture in the lipid-associated conformation. The relationship between reduced lipid association and reduced immune stimulating activity supports the hypothesis that apoLp-III-induced immune activation is triggered by the conformational change of the protein.

Amino Acid Substitution↗
PubMed2001

[The practice of compulsory patient commitment].

In Switzerland civil law allows compulsory hospitalization under defined circumstances. It is in the power of municipal authorities to decide on compulsory treatment, though in many of the Swiss cantons this power has been delegated to physicians. This paper first specifies the requirements for medical certificates directing compulsory hospitalization. Then 100 not selected medical certificates from 1997-2000 are compared to these requirements. Only 21% of the certificates met with all the requirements of form and content, nearly half of them showed formal deficiencies. The certificates issued by psychiatrists (n = 44) turned out to be more correct and complete in form and content than the certificates issued by not psychiatric hospital doctors (n = 26) and those issued by general practitioners (n = 30). It seems that not specialized (not psychiatric) doctors, who are rarely confronted with patients requiring compulsory treatment, are overcharged with this delicate and demanding task. To blame is also the passivity of the municipal authorities, who do not exercise their supervision task and seem to be happy having delegated the delicate problem of compulsory hospitalization to physicians.

Commitment of Persons with Psychiatric Disorders↗
PubMed2001

Molecular characterization of the 56-kDa CYP153 from Acinetobacter sp. EB104.

CYP153 a cytochrome P450 from Acinetobacter sp. EB104 catalyzes the hydroxylation of unsubstituted n-alkanes. We have decided to use the CYP153 system as a model for mechanistic studies on regioselective n-alkane oxidation and the interaction of hydrophobic substrates with soluble enzymes. Here the molecular cloning of the CYP153 gene is reported. Single specific primer PCR was applied to yield the whole gene sequence via chromosomal walks. CYP153 consists of 497 amino acids (M(r) = 56 kDa) and thus represents an unusually long bacterial P450, containing all P450 typical structural elements. It constitutes the new P450 family CYP153. The prolonged N-terminus of about 90 amino acids does not contain a so far known membrane-anchoring sequence but a 28-amino acid long amphipathic helix. The relevance of the remarkably long N-terminus and of other sequence motives like the hydrophobic F-G loop is discussed with respect to substrate binding and recognition.

Acinetobacter↗
PubMed2001

Pseudogaps in the 2D Hubbard Model.

We study the pseudogaps in the spectra of the 2D Hubbard model using both finite-size and dynamical cluster approximation (DCA) quantum Monte Carlo calculations. At half-filling, a charge pseudogap, accompanied by non-Fermi-liquid behavior in the self-energy, is shown to persist in the thermodynamic limit. The DCA (finite-size) method systematically underestimates (overestimates) the width of the pseudogap. A spin pseudogap is not seen at half-filling. At finite doping, a divergent d-wave pair susceptibility is observed.

Journal Article↗
PubMed2001

Fast elevation of the intramyocellular lipid content in the presence of circulating free fatty acids and hyperinsulinemia: a dynamic 1H-MRS study.

The influence of a short-term elevation of free fatty acids (FFAs) on intramyocellular lipids (IMCL) under hyperinsulinemic conditions was monitored in five healthy male subjects in the course of a 5-hr hyperinsulinemic glucose clamp. During the glucose clamp a lipid emulsion (Intralipid 20(R)) and heparin were administered intravenously. IMCL was quantified in the tibialis anterior (TA) and the soleus (SOL) muscle by (1)H-MRS. A rapid elevation of the IMCL pool was found in both muscles (61% in TA and 22% in SOL) in the 5-hr time period. A control hyperinsulinemic glucose clamp in the same study group, repeated without elevation of circulating FFAs, did not lead to significant changes in IMCL for both muscles. The present study shows for the first time that only the combination of high concentrations of FFAs and insulin lead to marked storage of lipids in skeletal muscle cells in humans. Magn Reson Med 45:179-183, 2001.

Adult↗
PubMed2001

NHE1-inhibitor cariporide prevents the transient reperfusion-induced shortening of the monophasic action potential after coronary ischemia in pigs.

During myocardial ischemia intracellular acid load increases as a consequence of anaerobic metabolism. Exchange of excessive protons for sodium via the sodium proton exchanger type 1 (NHE1) is supposed to cause intracellular sodium accumulation. The NHE1 inhibitor cariporide has been shown to inhibit ischemia and reperfusion-induced ventricular fibrillation (VF) but the mechanisms are not fully understood. During early reperfusion transient shortening of the action potential has been reported, which renders the heart susceptible to reentrant arrhythmias. In anesthetized pigs subjected to 10 min of left circumflex coronary artery (LCX) occlusion and reperfusion we have investigated whether NHE1 is involved in reperfusion-induced shortening of the monophasic action potential (MAP) taken with an epicardial probe over the ischemic area. In control pigs (n = 7) a moderate decrease in the duration of the MAP at 50 % repolarization (MAPD50) occurred during ischemia reaching 78.8 +/- 5.0% of the pre-ischemic duration at 5 min (p < 0.01) and 87.3 +/- 7.6 % after 10 min. An additional, transient but marked shortening occurred during the first 2 min of reperfusion, which fully recovered after 4 min. At 50 sec of reperfusion MAPD50 fell to 53.1 +/- 8.2 % of the pre-ischemic value corresponding to 90.1 +/- 20.2 msec of reperfusion-induced shortening. Cariporide, 3 mg/kg i.v. 5 min before occlusion (n = 6), totally prevented reperfusion-induced MAP shortening while having no effect on MAPD50 during ischemia. In conclusion, our data suggest that the immediate, transient, but strong action potential shortening during early reperfusion after 10 min of coronary ischemia is due to the activity of the NHE1.

Action Potentials↗
PubMed2001

Molecular characterisation and expression of two venom allergen-like protein genes in Heterodera glycines.

Secretory proteins encoded by genes expressed in the oesophageal gland cells of plant-parasitic nematodes have key roles in nematode parasitism of plants. Two venom allergen-like protein cDNAs (designated hg-vap-1 and hg-vap-2)were isolated from Heterodera glycines gland cell cDNA libraries. Both cDNAs hybridised to genomic DNA of H. glycines in Southern blots. The hg-vap-1 cDNA contained an open reading frame encoding 215 amino acids with the first 25 amino acids being a putative secretion signal. The hg-vap-2 cDNA contained an open reading frame encoding 212 amino acids with the first 19 amino acids being a putative secretion signal. Genes of hg-vap-1 and hg-vap-2 contained four introns, which ranged in size from 44 to 574 bp, and five exons ranging in size from 43 to 279 bp. In situ hybridisation analyses showed that mRNAs of both vap genes accumulated specifically in the subventral gland cells of H. glycines during parasitism. The gland cell-specific expression and presence of predicted secretion signal peptides in both VAPs suggest that these proteins are secreted from the nematode and may play a role in the infection of host plants by this parasite.

Allergens↗
PubMed2001

Identification of putative parasitism genes expressed in the esophageal gland cells of the soybean cyst nematode Heterodera glycines.

Cloning parasitism genes encoding secretory proteins expressed in the esophageal gland cells is the key to understanding the molecular basis of nematode parasitism of plants. Suppression subtractive hybridization (SSH) with the microaspirated contents from Heterodera glycines esophageal gland cells and intestinal region was used to isolate genes expressed preferentially in the gland cells of parasitic stages. Twenty-three unique cDNA sequences from a SSH cDNA library were identified and hybridized to the genomic DNA of H. glycines in Southern blots. Full-length cDNAs of 21 clones were obtained by screening a gland-cell long-distance polymerase chain reaction cDNA library. Deduced proteins of 10 clones were preceded by a signal peptide for secretion, and PSORT II computer analysis predicted eight proteins as extracellular, one as nuclear, and one as plasmalemma localized. In situ hybridization showed that four of the predicted extracellular clones were expressed specifically in the dorsal gland cell, one in the subventral gland cells, and three in the intestine in H. glycines. The predicted nuclear clone and the plasmalemma-localized clone were expressed in the subventral gland cells and the dorsal gland cell, respectively. SSH is an efficient method for cloning putative parasitism genes encoding esophageal gland cell secretory proteins that may have a role in H. glycines parasitism of soybean.

Animals↗
PubMed2001

Signal peptide-selection of cDNA cloned directly from the esophageal gland cells of the soybean cyst nematode Heterodera glycines.

Secretions from the esophageal gland cells of plant-parasitic nematodes play critical roles in the nematode-parasitic cycle. A novel method to isolate cDNA encoding putative nematode secretory proteins was developed that utilizes mRNA for reverse transcription-polymerase chain reaction derived from microaspiration of the esophageal gland cell contents of parasitic stages of the soybean cyst nematode Heterodera glycines. The resulting H. glycines gland cell cDNA was cloned into the pRK18 vector, and plasmid DNA was transformed into a mutated yeast host for specific selection of cDNA inserts that encode proteins with functional signal peptides. Of the 223 cDNA clones recovered from selection in yeast, 97% of the clones encoded a predicted signal peptide. Fourteen unique cDNA clones hybridized to genomic DNA of H. glycines on Southern blots and, among them, nine cDNA clones encoded putative extracellular proteins, as predicted by PSORT II computer analysis. Four cDNA clones hybridized to transcripts within the dorsal esophageal gland cell of parasitic stages of H. glycines, and in situ hybridization within H. glycines was not detected for eight cDNA clones. The protocol provides a direct means to isolate potential plant-parasitic nematode esophageal gland secretory protein genes.

Animals↗
PubMed2001

Effects of intravenous and dietary lipid challenge on intramyocellular lipid content and the relation with insulin sensitivity in humans.

An increased intramyocellular lipid (IMCL) content, as quantified by (1)H-magnetic resonance spectroscopy ((1)H-MRS), is associated with reduced insulin sensitivity. At present, it is unclear which factors determine IMCL formation and how rapidly IMCL accumulation can be induced. We therefore studied the impact of hyperinsulinemia and elevated circulating nonesterified fatty acid (NEFA) levels on IMCL formation and insulin sensitivity. We further evaluated the influence of a high-fat diet on IMCL storage. In the infusion protocol, 12 healthy male subjects underwent a 6-h hyperinsulinemic-euglycemic glucose clamp with concomitant infusion of Intralipid plus heparin. IMCL was quantified by (1)H-MRS in soleus (SOL) and tibialis anterior (TA) muscle at baseline and then every hour. IMCL levels started to increase significantly after 2 h, reaching a maximum of 120.8 +/- 3.4% (SOL) and 164.2 +/- 13.8% (TA) of baseline after 6 h (both P < 0.05). In parallel, the glucose infusion rate (GIR) decreased progressively, reaching a minimum of 60.4 +/- 5.4% of baseline after 6 h. Over time, the GIR was strongly correlated with IMCL in TA (r = -0.98, P < or = 0.003) and SOL muscle (r = -0.97, P < or = 0.005). In the diet protocol, 12 male subjects ingested both a high-fat and low-fat diet for 3 days each. Before and after completion of each diet, IMCL levels and insulin sensitivity were assessed. After the high-fat diet, IMCL levels increased significantly in TA muscle (to 148.0 +/- 16.9% of baseline; P = 0.005), but not in SOL muscle (to 114.4 +/- 8.2% of baseline; NS). Insulin sensitivity decreased to 83.3 +/- 5.6% of baseline (P = 0.033). There were no significant changes in insulin sensitivity or IMCL levels after the low-fat diet. The effects of the high-fat diet showed greater interindividual variation than those of the infusion protocol. The data from the lipid infusion protocol suggest a functional relationship between IMCL levels and insulin sensitivity. Similar effects could be induced by a high-fat diet, thereby underlining the physiological relevance of these observations.

Adult↗
PubMed2000

Beam splitter for guided atoms.

We have designed and experimentally studied a simple beam splitter for guided atoms realized with a current carrying Y-shaped wire nanofabricated on a surface (atom chip). Such a Y-configuration beam splitter has many advantages compared to conventional designs based on tunneling, especially that it will enable robust beam splitting. This and other similar designs can be integrated into more sophisticated surface-mounted atom optical devices at the mesoscopic scale.

Journal Article↗
PubMed2000

d-wave superconductivity in the hubbard model

The superconducting instabilities of the doped repulsive 2D Hubbard model are studied in the intermediate to strong coupling regime with the help of the dynamical cluster approximation. To solve the effective cluster problem we employ an extended noncrossing approximation, which allows for a transition to the broken symmetry state. At sufficiently low temperatures we find stable d-wave solutions with off-diagonal long-range order. The maximal T(c) approximately 150 K occurs for a doping delta approximately 20% and the doping dependence of the transition temperatures agrees well with the generic high- T(c) phase diagram.

Journal Article↗
PubMed2000

Controlling cold atoms using nanofabricated surfaces: atom chips

Atoms can be trapped and guided using nanofabricated wires on surfaces, achieving the scales required by quantum information proposals. These atom chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

Journal Article↗
PubMed2000

Identification of a major facilitator protein from Escherichia coli involved in efflux of metabolites of the cysteine pathway.

A chromosomal fragment has been identified in a gene bank from Escherichia coli, which augmented the yield of cysteine in an industrial production strain. Subcloning and genetic analysis showed that an open reading frame coding for a product of 299 amino acids (Orf299) was responsible. Orf299 was synthesized in the T7 polymerase/promoter system and exhibited the properties of an integral membrane protein. Mutational interruption of orf299 did not cause a distinct phenotype; however, transformants overexpressing orf299 had lost the ability to grow in minimal medium unless it was supplemented with a source of reduced sulphur compounds, and they excreted considerable amounts of cysteine and O-acetyl-L-serine, especially in the presence of thiosulphate. Most of the cysteine was found to be masked in 2-methyl-2,4-thiazolidinedicarboxylic acid. N-acetyl-L-serine was also present in the medium, but it is open to question whether it represents a primary excretion product. Measurement of the induction status of the cysteine regulon by means of a cysK'-'lacZ gene fusion demonstrated that the regulon is not induced upon growth in the presence of a poor sulphur source and that the introduction of a constitutive cysB allele alleviates this deficiency. The results indicate that orf299 codes for an export pump for different metabolites of the cysteine pathway. Its relation to other efflux systems and the physiological role are discussed.

Amino Acid Sequence↗
PubMed1999

Crystal structure of mistletoe lectin I from Viscum album.

The crystal structure of the ribosome-inactivating protein (RIP) mistletoe lectin I (ML-I) from Viscum album has been solved by molecular replacement techniques. The structure has been refined to a crystallographic R-factor of 24.5% using X-ray diffraction data to 2.8 A resolution. The heterodimeric 63-kDa protein consists of a toxic A subunit which exhibits RNA-glycosidase activity and a galactose-specific lectin B subunit. The overall protein fold is similar to that of ricin from Ricinus communis; however, unlike ricin, ML-I is already medically applied as a component of a commercially available misteltoe extract with immunostimulating potency and for the treatment of human cancer. The three-dimensional structure reported here revealed structural details of this pharmaceutically important protein. The comparison to the structure of ricin gives more insights into the functional mechanism of this protein, provides structural details for further protein engineering studies, and may lead to the development of more effective therapeutic RIPs.

Abrin↗
PubMed1999

[Psychosis, language and literature].

There have always been debates about possible correlations between creative genius and mental illness, not only among psychiatrists but also among scientists of art and literature. Especially modern literary texts may show formal similarities to psychotic speech, which leads to the question, whether not only artists, but also people in psychotic states are able to create literature. This article points out the loosened semantic stability in psychotic speech, which equals a loss of common ground in the use of signs and symbols. In terms of Gadamer's hermeneutics, texts produced by psychotic people cannot be understood, they are mere form. Even in hermetic literary texts, the semantic code can be offended, but in deliberate artistic intention, which finds its communicative purpose in breaking the symbolic order.

Creativity↗