PubMed Health⌕ Search

Biomedical subjects

T Wenzel

Publications and source records attributed to T Wenzel.

At least 19 recordsLinked to original sources
PubMed2003

Phase analysis of superconducting polycrystalline MgB(2).

Superconducting MgB(2) ceramics were prepared and yield superconducting transition temperatures of about 39 K. For covering the various length scales on which inhomogeneities appear in MgB(2), electron-probe micro-analysis (EPMA) and analytical transmission electron microscopy (TEM) were applied for a phase analysis. Particularly useful were the preliminary electron spectroscopic imaging (ESI) results in the TEM. It could be shown by EPMA that the microstructure consists of a Mg-B-O matrix and boron-rich secondary phases of composition close to MgB(12). It was unclear in which form oxygen was present in the superconducting matrix. By combining the acquisition of B-K and O-K edge jump ratio images and energy-dispersive X-ray spectroscopy in the TEM, we could prove that the matrix consists of superconducting MgB(2) and MgO. Most of the MgO precipitates and grains appear with diameters between 20 and 300 nm. The size distribution of MgO was inhomogeneous and oxygen-rich areas of dimensions >1 microm were also observed. Edge jump ratio images obtained by ESI were analysed for determining the signal values and effects of multiple inelastic scattering.

Boron Compounds↗
PubMed2002

Relation between depression and anxiety in dystonic patients: implications for clinical management.

Past clinical research has identified depression as the most common psychiatric disorder associated with cervical dystonia (CD). The purpose of our study is to document different patterns of psychopathology, the frequency of psychiatric disorders, and possible correlation with the neurological disorder in patients with CD. Forty patients with CD were investigated to assess levels of psychopathology on two self-rated scales: the Beck Depression Inventory (BDI) and Symptom Check List (SCL-90). To determine the presence of psychiatric disorders, the patients were evaluated using the standard instrument in the DSM-III-R (Structured Clinical Interview Schedule, SCID). A small group of dystonic patients (12%) had higher levels of psychopathology, with significant amounts of concomitant anxiety and depression on the BDI and SCL-90. SCID criteria for at least one psychiatric disorder were fulfilled in 22 patients (55%), including both the lifetime and current diagnoses. The most frequent diagnostic categories were anxiety (40%) and major depressive disorders (37.5%). In 17 patients (42.5%), criteria for at least one lifetime diagnosis were fulfilled prior to the onset of CD. Psychiatric evaluation does not indicate one specific disorder associated with CD. The presence of anxiety and depression symptoms before and during the course of dystonia, without a possible causal relationship, could mean that the alteration of a chain of physiological events in the central nervous system may not lead to a single clinical picture. The relatively high overall lifetime prevalence of anxiety and depressive disorders may indicate the need for a broader diagnostic and therapeutic approach to patients with focal dystonia.

Adult↗
PubMed2000

Decay times of surface plasmon excitation in metal nanoparticles by persistent spectral hole burning

We describe a new technique to determine the homogeneous linewidths of surface plasmon resonances of metal nanoparticles and thus measure the decay time of this collective electron excitation. The method is based on spectral hole burning and has been applied to supported oblate Ag particles with radii of 7.5 nm. From the experimental results and a theoretical model of hole burning the linewidth of 260 meV corresponding to a decay time of 4.8 fs was extracted. This value is shorter than expected for damping by bulk electron scattering. We conclude that additional damping mechanisms have been observed and reflect confinement of the electrons in nanoparticles with sizes below 10 nm.

Journal Article↗
PubMed2000

Psychiatric disorders in patients with blepharospasm - a reactive pattern?

OBJECTIVE: The purpose of this study was to assess the life-time prevalence of all major psychiatric disorders in patients suffering from blepharospasm. METHOD: A total of 31 consecutive patients with blepharospasm attending the Department of Neurology were interviewed at the Department of Psychiatry at the University of Vienna. Patients had been submitted to standard neurological diagnostic procedures, psychiatric diagnoses were made with the help of the SCID, functional impairment was assessed by the General Assessment of Functioning Scale (GAF). RESULTS: A current or life-time psychiatric diagnosis was made for 22 patients (71%). The most frequent disorders were depressive disorders, mainly major depression (five patients, 16.1%), secondary dysthymia (six patients, 19.3%), and recurrent major depression (five patients, 16.1%). A diagnosis of simple phobia was made for seven patients (22.5%), for obsessive-compulsive disorder in three patients (9.6%). The mean GAF score of our sample was 63.1%. CONCLUSION: In contrast to previously published results, we did not find a high rate of a single specific disorder or patterns in our study sample, though by the inclusion of life-time diagnostic criteria, the majority of patients fulfilled criteria for at least one diagnosis. This might indicate the considerable negative impact of blepharospasm on the patients' lives.

Aged↗
PubMed1999

Dimensions of quality of life and self-monitoring therapy with oral anticoagulants--still research or everyday practice?

In correlation with increased life expectancy of patients, quality of life (QOL) has become a factor of increasing interest by the patient himself and also of importance in health-care planning and recruitment of financial resources. In this context, self-monitoring of long-term anticoagulant treatment might be a strategy that could mean a step forward in health-related as well as general life satisfaction for patients participating in self-monitoring programs. Also, the new strategy of increased home-control of anticoagulant treatment illustrates the complexity of multiple factors that can lead to changes in the subjective feeling and objective aspects of QOL. Our intention in a pilot study was to probe the feasibility of QOL research and relevant factors of influence by retrospectively evaluating data from two groups of outpatients seen in a large treatment center. The high frequency (n = 8 in sample 2) of disturbed sleep as a simple screening indicator stresses the probable importance of undetected depression, which might require treatment and could confound research as to QOL. Instruments to measure QOL in oral anticoagulation self-monitoring should therefore be adapted to the heterogeneous structure of factors in the target population, and include psychological parameters, especially in regard to health-related locus of control and mood.

Administration, Oral↗
PubMed1999

The effect of self-monitoring the INR on quality of anticoagulation and quality of life.

In a prospective cohort study the influence of self-monitoring of the International Normalized Ratio (INR) was examined on 100 consecutive patients for a period of 6 months. Quality of life changed in a positive way. Independence and better organization of vacation and spare time were the most frequently mentioned advantages of the new method. Quality of anticoagulation by using a self-monitoring device was improved compared to the values before using the self-monitoring device. For measuring the INR, the usage of a portable monitor as the primary method can be recommended in selected patients receiving oral long-term anticoagulation.

Anticoagulants↗
PubMed1998

Bone scintigraphy in screening of torture survivors.

BACKGROUND: In most developed countries, survivors of physical torture inflicted for political, religious, or ethnic reasons face ever more stringent review when seeking asylum. In Austria, asylum seekers are required by immigration authorities to undergo medical examination as part of the review. Bone scintigraphy can detect bone lesions that are not detectable clinically or radiologically. We assessed the value of bone scintigraphy as corroboration of alleged injuries. METHODS: Human-rights organisations referred 25 asylum seekers to us from countries where torture is practised. We included patients who claimed to have been beaten by the security forces in their home country because of political or religious conviction or ethnic origin. Injuries had been inflicted 4 months to 5 years earlier. The patients (three women, 22 men) from 12 countries were categorised retrospectively into two groups: group A (n=12), tortured with blows from hard objects, and group B (n=13), tortured with blows from fists and kicks. We also used a control group of 25 individuals with the same age and sex distribution from the same countries who had no history of torture. FINDINGS: In group A, bone scans showed abnormalities in the area of alleged injury in all patients, whereas radiography was positive in only five patients. In group B, bone scans in the alleged areas of damage were positive in seven patients, but radiography yielded no positive outcomes. Among the controls there was one abnormal scan due to a known coxarthrosis. INTERPRETATION: Our preliminary results suggest that bone scintigraphy is a sensitive, non-invasive tool to document trauma some years after the actual injury.

Bone and Bones↗
PubMed1998

Globus sensation: pharyngoesophageal function, psychometric and psychiatric findings, and follow-up in 88 patients.

BACKGROUND: The globus sensation has been widely regarded as psychogenic, but organic disorders were found to be etiologically significant. OBJECTIVE: To investigate the structural, functional, psychological, and psychiatric factors possibly eliciting the globus sensation and influencing its course. METHODS: Eighty-eight patients, 67 women and 21 men (aged 22-71 years), referred to 2 tertiary care centers underwent history taking, otolaryngological examination, pharyngoesophageal videofluoroscopy and manometry, psychosocial evaluation, psychometric tests, psychiatric interview, and when indicated, esophagogastroduodenoscopy, esophageal bolus transport, gastroesophageal reflux, and gastric emptying studies. According to revealed disorders, therapy was initiated, and the outcome was studied. RESULTS: Only 15 patients had normal pharyngoesophageal function; of these 15, 6 had chronic tonsillitis or pharyngitis, 3 had thyroid adenomata, 4 had cervical spondylosis, and 1 each had dry oropharyngeal mucosa and chronic bronchitis. Of the other 73 patients, 2 had pharyngeal dysfunction, 24 had achalasia, 1 had diffuse esophageal spasms, 3 had "nutcracker esophagus," 30 had nonspecific esophageal motor disorders, and 13 had gastroesophageal reflux. Psychometry revealed no more anxiety and depression than in general medical outpatients. Of 58 patients interviewed, 37 met criteria for psychiatric disorders. Psychometric scores and psychiatric characteristics were unrelated to the sensation's course. Therapy was recommended, but only 26 patients were treated accordingly; 22 received nonspecific treatment. Follow-up 3 to 59 months later revealed that the sensation had vanished in 13 patients who had received specific treatment, 5 who had received nonspecific treatment, and 6 who had received no treatment; it was alleviated in 10 who had received specific treatment, 13 who had received nonspecific treatment, and 9 who had received no treatment; and it was unchanged in 3 who had received specific treatment, 5 who had received nonspecific treatment, and 23 patients who had received no treatment. CONCLUSIONS: Pharyngoesophageal disorders may be sensed only vaguely, inducing the globus sensation. Psychological and psychiatric characteristics could be relevant to the discomfort experienced but are unlikely to be etiologically significant.

Adult↗
PubMed1998

The Pichia pastoris dihydroxyacetone kinase is a PTS1-containing, but cytosolic, protein that is essential for growth on methanol.

Dihydroxyacetone kinase (DAK) is essential for methanol assimilation in methylotrophic yeasts. We have cloned the DAK gene from Pichia pastoris by functional complementation of a mutant that was unable to grow on methanol. An open reading frame of 1824 bp was identified that encodes a 65.3 kDa protein with high homology to DAK from Saccharomyces cerevisiae. Although DAK from P. pastoris contained a C-terminal tripeptide, TKL, which we showed can act as a peroxisomal targeting signal when fused to the green fluorescent protein, the enzyme was primarily cytosolic. The TKL tripeptide was not required for the biochemical function of DAK because a deletion construct lacking the DNA encoding this tripeptide was able to complement the P. pastoris dak delta mutant. Peroxisomes, which are essential for growth of P. pastoris on methanol, were present in the dak delta mutant and the import of peroxisomal proteins was not disturbed. The dak delta mutant grew at normal rates on glycerol and oleate media. However, unlike the wild-type cells, the dak delta mutant was unable to grow on methanol as the sole carbon source but was able to grow on dihydroxyacetone at a much slower rate. The metabolic pathway explaining the reduced growth rate of the dak delta mutant on dihydroxyacetone is discussed. The nucleotide sequence reported in this paper has been submitted to GenBank with Accession Number AF019198.

Amino Acid Sequence↗
PubMed1998

A mobile PTS2 receptor for peroxisomal protein import in Pichia pastoris.

Using a new screening procedure for the isolation of peroxisomal import mutants in Pichia pastoris, we have isolated a mutant (pex7) that is specifically disturbed in the peroxisomal import of proteins containing a peroxisomal targeting signal type II (PTS2). Like its Saccharomyces cerevisiae homologue, PpPex7p interacted with the PTS2 in the two-hybrid system, suggesting that Pex7p functions as a receptor. The pex7Delta mutant was not impaired for growth on methanol, indicating that there are no PTS2-containing enzymes involved in peroxisomal methanol metabolism. In contrast, pex7Delta cells failed to grow on oleate, but growth on oleate could be partially restored by expressing thiolase (a PTS2-containing enzyme) fused to the PTS1. Because the subcellular location and mechanism of action of this protein are controversial, we used various methods to demonstrate that Pex7p is both cytosolic and intraperoxisomal. This suggests that Pex7p functions as a mobile receptor, shuttling PTS2-containing proteins from the cytosol to the peroxisomes. In addition, we used PpPex7p as a model protein to understand the effect of the Pex7p mutations found in human patients with rhizomelic chondrodysplasia punctata. The corresponding PpPex7p mutant proteins were stably expressed in P. pastoris, but they failed to complement the pex7Delta mutant and were impaired in binding to the PTS2 sequence.

Acetyl-CoA C-Acyltransferase↗
PubMed1998

Psychiatric comorbidity in patients with spasmodic torticollis.

Several studies have reported raised levels of psychopathology based on self-rating scales in patients with spasmodic torticollis. Recent publications have also proposed that psychopathology, especially symptoms of depression, might be a reaction to dystonia or constitute a nonspecific reaction pattern. To determine the actual frequency of psychiatric disorders, we evaluated 44 patients with spasmodic torticollis (20 female, 24 male; mean age 43.6 years, SD 10.4) using the standard instrument for psychiatric diagnosis in the DSM-III-R (Structured Clinical Interview Schedule, SCID). The SCID permits retrospective diagnosis for most of the major psychiatric disorders, including the time before onset of dystonia. SCID criteria for at least one psychiatric disorder were fulfilled in 65.9% of patients, including both lifetime and current diagnosis. The most frequent diagnostic categories were panic disorder with or without agoraphobia (29.5%), major depressive disorder (25%), substance abuse (13.6%), and obsessive compulsive disorders (6.8%) were diagnosed less frequently. The patient-recalled onset of psychiatric symptoms preceded onset of torticollis symptoms in 43.2% of those investigated.

Adolescent↗
PubMed1998

[Blepharospasm and acupuncture--initial results of a treatment trial].

Blepharospasm is a dystonia of the orbicularis muscle. The background is still unknown, but it appears together with organic and psychic diseases. The therapy with botulinum toxine is symptomatically but efficient. Because of the relaxing effect on the psychological and autonomous nervous disorders we performed a pilot study with acupuncture. There was a neurological observation first, then a ophthalmologic examination of the ocular surface. Blepharospasm was measured by the Visual Analogue Scale (VAS), the social disorders by the Elston-Score. We performed acupuncture treatment 10 times once weekly. The used points were local points with higher sensitivity, and points with empiric relaxation effect. 5 patients were included. The mean of Elston score was 3 before acupuncture and 4 after acupuncture. The VAS increased from 33.3 to 69/100 points. But there were fluctuations of dystonias. In conclusion acupuncture maybe a good method for this difficult disease additionally.

Acupuncture Points↗
PubMed1997

Visualization of the peroxisomal compartment in living mammalian cells: dynamic behavior and association with microtubules.

Peroxisomes in living CV1 cells were visualized by targeting the green fluorescent protein (GFP) to this subcellular compartment through the addition of a COOH-terminal peroxisomal targeting signal 1 (GFP-PTS1). The organelle dynamics were examined and analyzed using time-lapse confocal laser scanning microscopy. Two types of movement could be distinguished: a relatively slow, random, vibration-like movement displayed by the majority (approximately 95%) of the peroxisomes, and a saltatory, fast directional movement displayed by a small subset (approximately 5%) of the peroxisomes. In the latter instance, peak velocities up to 0.75 micron/s and sustained directional velocities up to 0.45 micron/s over 11.5 microns were recorded. Only the directional type of motion appeared to be energy dependent, whereas the vibrational movement continued even after the cells were depleted of energy. Treatment of cells, transiently expressing GFP-PTS1, with microtubule-destabilizing agents such as nocodazole, vinblastine, and demecolcine clearly altered peroxisome morphology and subcellular distribution and blocked the directional movement. In contrast, the microtubule-stabilizing compound paclitaxel, or the microfilament-destabilizing drugs cytochalasin B or D, did not exert these effects. High resolution confocal analysis of cells expressing GFP-PTS1 and stained with anti-tubulin antibodies revealed that many peroxisomes were associated with microtubules. The GFP-PTS1-labeled peroxisomes were found to distribute themselves in a stochastic, rather than ordered, manner to daughter cells at the time of mitosis.

Animals↗
PubMed1996

Isolation and characterization of Pas2p, a peroxisomal membrane protein essential for peroxisome biogenesis in the methylotrophic yeast Pichia pastoris.

The pas2 mutant of the methylotrophic yeast Pichia pastoris is characterized by a deficiency in peroxisome biogenesis. We have cloned the PpPAS2 gene by functional complementation and show that it encodes a protein of 455 amino acids with a molecular mass of 52 kDa. In a Pppas2 null mutant, import of both peroxisomal targeting signal 1 (PTS1)- and PTS2-containing proteins is impaired as shown by biochemical fractionation and fluorescence microscopy. No morphologically distinguishable peroxisomal structures could be detected by electron microscopy in Pppas2 null cells induced on methanol and oleate, suggesting that PpPas2p is involved in the early stages of peroxisome biogenesis. PpPas2p is a peroxisomal membrane protein (PMP) and is resistant to extraction by 1 M NaCl or alkaline sodium carbonate, suggesting that it is a peroxisomal integral membrane protein. Two hydrophobic domains can be distinguished which may be involved in anchoring PpPas2p to the peroxisomal membrane. PpPas2p is homologous to the Saccharomyces cerevisiae Pas3p. The first 40 amino acids of PpPas2p, devoid of the hydrophobic domains, are sufficient to target a soluble fluorescent reporter protein to the peroxisomal membrane, with which it associates tightly. A comparison with the membrane peroxisomal targeting signal of PMP47 of Candida boidinii revealed a stretch of positively charged amino acids common to both sequences. The role of peroxisomal membrane targeting signals and transmembrane domains in anchoring PMPs to the peroxisomal membrane is discussed.

ATP-Binding Cassette Transporters↗
PubMed1995

[Globus sensation].

Explore the source record for details and available documents.

Conversion Disorder↗