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A Albrecht

Publications and source records attributed to A Albrecht.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of roflumilast, an oral anti-inflammatory, with beclomethasone dipropionate in the treatment of persistent asthma.

BACKGROUND: Roflumilast is an oral, once-daily phosphodiesterase 4 inhibitor with anti-inflammatory activity in development for the treatment of asthma. Roflumilast was compared with inhaled beclomethasone dipropionate (BDP) in patients with asthma. METHODS: In a double blind, double-dummy, randomized, noninferiority study, 499 patients (forced expiratory volume in 1 s [FEV1] = 50-85% predicted) received roflumilast 500 microg once daily or BDP 200 microg twice daily (400 microg/day) for 12 weeks. Lung function and adverse events were monitored. RESULTS: Roflumilast and BDP significantly improved FEV1 by 12% (270 +/- 30 ml) and 14% (320 +/- 30 ml), respectively (P < 0.0001 vs baseline). Roflumilast and BDP also significantly improved forced vital capacity (FVC) (P < 0.0001 vs baseline). There were no significant differences between roflumilast and BDP with regard to improvement in FEV1 and FVC. Roflumilast and BDP showed small improvements in median asthma symptom scores (-0.82 and -1.00, respectively) and reduced rescue medication use (-1.00 and -1.15 median puffs/day, respectively; P < 0.0001 vs baseline). These small differences between roflumilast and BDP were not considered clinically relevant. Both agents were well tolerated. CONCLUSIONS: Once daily, oral roflumilast 500 microg was comparable with inhaled twice-daily BDP (400 microg/day) in improving pulmonary function and asthma symptoms, and reducing rescue medication use in patients with asthma.

Administration, Inhalation↗
PubMed2006

Genes and neurons: molecular insights to fear and anxiety.

Experimental animal models provide an important tool for the identification of inheritable components of fear and anxiety. 'Pavlovian' fear conditioning has been tremendously successful to characterize the neuronal circuitry and cellular mechanisms of the formation, consolidation and extinction of fear memories. Here we summarize recent progress that has led to the identification of gene products contributing to such experience-dependent changes in fear and anxiety and may guide the search for genetic factors involved in the development and treatment of human anxiety disorders.

Amygdala↗
PubMed2005

Brain tumour surgery in the vicinity of short-term memory representation--results of neuronavigation using fMRI images.

OBJECTIVE: Functional information concerning the surrounding brain is mandatory for a good clinical outcome in brain tumour surgery. The value of fMRI to detect the motorcortex and Broca's area is widely accepted today. If an appropriate paradigm is used, short-term memory areas can be visualized as well. Obviously this information must be integrated into cranial neuronavigation for an appropriate intra-operative use. We report our first experiences with the direct integration of short-term memory fMRI into cranial neuronavigation. METHOD: From January 2001 to March 2002 14 patients were operated on for intracranial tumours with short-term memory fMRI imaging, using the "two-back-paradigm". Both pre- and postoperatively, the short-term memory of all patients was tested additionally by a standardized test battery including 16 different verbal and visuo-spatial items. RESULTS: In all 14 patients the general level of working memory capacity was preserved after surgery. The visuo-spatial performance was kept unchanged or deteriorated slightly, the alertness slightly worsened as well, but we found an improvement in verbal test items. CONCLUSION: The two-back paradigm is able to visualize verbal memory tasks in fMRI. For visuo-spatial items, a new paradigm has to be designed. In contrast to deep seated brain lesions, focal cortical impairments do not lead to obvious and serious memory deficits. Therefore, the aim of gross total tumour removal has to be balanced against the aim of preservation of short-term memory fields. Nevertheless, the knowledge of the localization of cortical short-term memory fields may combine both aims during navigated brain tumour surgery, thus preserving the patient with a better quality of life.

Adult↗
PubMed2005

Is the transfer factor a relevant tool to assess the soil-to-plant transfer of radionuclides under field conditions?

The radiological impact of radionuclides released to the terrestrial environment is usually predicted with mathematical models in which the transfer of radionuclides from soil to the plant is described with the transfer factor (TF). This paper questions the validity of the protocols proposed by the International Atomic Energy Agency to measure TF in the field and in greenhouses conditions. We grew maize (Zea mays L.) both in the field after a surface application of radionuclides ((54)Mn, (57)Co, (65)Zn, and (134)Cs) and in a greenhouse with the same soil that has received the same fertilization and that had been previously sieved and homogeneously labeled with the same radionuclides before being repacked in pots. The analysis of the displacement of radionuclides in the field soil profile showed a higher concentration of the surface-applied radionuclides in the preferential flow path (PFP) in comparison to the soil matrix indicating that they infiltrated heterogeneously in the soil profile due to the structure-induced non-uniform water flow. A significantly higher recovery of (57)Co and (134)Cs was observed in the plants grown in the field soil, whereas no differences in the recovery of (54)Mn and (65)Zn between the two experiments were detected. These results suggest that (i) under field conditions the soil-to-plant transfer of radionuclides that co-exist as stable elements present at low concentrations in the soil and in the plant is higher than that measured under greenhouse conditions and (ii) the implicit assumption made when calculating the TF (that radionuclides are homogeneously distributed in the soil profile) is not valid, thereby preventing the calculation of an average concentration to obtain the TF parameter.

Models, Theoretical↗
PubMed2005

Soil microbial community response to land use change in an agricultural landscape of western Kenya.

Tropical agroecosystems are subject to degradation processes such as losses in soil carbon, nutrient depletion, and reduced water holding capacity that occur rapidly resulting in a reduction in soil fertility that can be difficult to reverse. In this research, a polyphasic methodology has been used to investigate changes in microbial community structure and function in a series of tropical soils in western Kenya. These soils have different land usage with both wooded and agricultural soils at Kakamega and Ochinga, whereas at Ochinga, Leuro, Teso, and Ugunja a replicated field experiment compared traditional continuous maize cropping against an improved N-fixing fallow system. For all sites, principal component analysis of 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles revealed that soil type was the key determinant of total bacterial community structure, with secondary variation found between wooded and agricultural soils. Similarly, phospholipid fatty acid (PLFA) analysis also separated wooded from agricultural soils, primarily on the basis of higher abundance of monounsaturated fatty acids, anteiso- and iso-branched fatty acids, and methyl-branched fatty acids in the wooded soils. At Kakamega and Ochinga wooded soils had between five 5 and 10-fold higher levels of soil carbon and microbial biomass carbon than agricultural soils from the same location, whereas total enzyme activities were also lower in the agricultural sites. Soils with woody vegetation had a lower percentage of phosphatase activity and higher cellulase and chitinase activities than the agricultural soils. BIOLOG analysis showed woodland soils to have the greatest substrate diversity. Throughout the study the two functional indicators (enzyme activity and BIOLOG), however, showed lower specificity with respect to soil type and land usage than did the compositional indicators (DGGE and PLFA). In the field experiment comparing two types of maize cropping, both the maize yields and total microbial biomass were found to increase with the fallow system. Moreover, 16S rRNA gene and PLFA analyses revealed shifts in the total microbial community in response to the different management regimes, indicating that deliberate management of soils can have considerable impact on microbial community structure and function in tropical soils.

Agriculture↗
PubMed2004

Percutaneous transarticular atlantoaxial screw fixation using a cannulated screw system and image guidance.

In 2000 a cannulated screw stabilization system for posterior cervical instrumentation was introduced in our department for use in complex cervical fixation procedures. A special feature of the system is the use of thin Kirschner wires for drilling the screw paths and then placing the self-drilling, cannulated screws securely over the wires. Percutaneous application of C1-C2 transarticular screws is possible through tubes. An optional "atlas-claw" provides additional stability in cases of C1-C2 stabilization. 17 patients (10 female, 7 male, mean age 60 years) with complex cervical disorders and instability of different origin were stabilized using the Neon System (Ulrich Co., Ulm, Germany). Pathology included atlantoaxial instability based on rheumatoid arthritis (n = 12), odontoid fracture (n = 4) and os odontoideum mobile (n = 1). Computed navigation (STN 4.0, Zeiss or vector vision spine, brain lab) was used in 14 cases. Transarticular C1-C2 screw fixation was performed in 14 cases (4 patients with direct C1 massa lateralis screw fixation), craniocervical fixation (C0-C2/C3) was done in 3 patients. Percutaneous application of the C1-C2 screws was used in 7 patients. Atlas claws were applied in 8 patients. There was one medial perforation of a C2 pedicle wall and one malposition of the screw in C2 without reaching the lateral mass of C1. After a mean follow-up of 9 months there were no hardware failures and stable fusion in those cases followed after 12 months or more. Clinical results were excellent or good in 14/16 patients. Cannulated screws are an effective alternative in complex stabilization procedures of the cervical spine. The presented system is technically comfortable and allows safe percutaneous screw application as well as inclusion of computed navigation with high accuracy.

Adult↗
PubMed2003

Behavior of a surface applied radionuclide and a dye tracer in structured and repacked soil monoliths.

There has been increasing evidence in recent years about the impact of soil structure on vadose zone hydrology and the distribution of surface applied chemical substances. We have carried out a combined dye and radionuclide tracer study on two monoliths from the same location, one structured and one repacked, as part of an ongoing study to investigate the link between preferential flow, leaching of surface applied substances and their distribution within the soil.A tracer solution containing 1300 Bq/L (58)Co and 0.31 micromol/L Sulforhodamine B (SB) was added with roughly constant irrigation during a period of three weeks. The dye served as a tracer for water movement within the soil and thus allowed linkage of the radiotracer ((58)Co) with the flow pattern. Both were monitored in the outflow and measured within profile sections after monolith disassembly. Preferential flow in the structured monolith promoted the bypass and transport of both tracers, although transport was impeded at depths greater than 30 cm by compacted soil and reduced hydraulic conductivity. Eighty four percent of radiocobalt and 8% of SB were found in the upper 4 cm of the structured monolith. The homogenized monolith, on the other hand, showed mostly chromatographic infiltration and a more efficient soil filtering capacity with 91% of radiocobalt and 20% SB residing in the upper 4 cm. Furthermore no tracer was found in the outflow of the homogenized monolith during normal to high irrigation or at greater depth within the monolith. We have related flow characteristics and sorption of radiotracers by quantifying dye distributions and radionuclide activities throughout the profiles. Activities within the flow paths are up to 20-times higher than those measured in the soil matrix, and a fraction of radiocobalt follows the dye tracer in spite of cobalt's low mobility. The dye can thus be used to trace radionuclide distribution within the soil block.

Cobalt Radioisotopes↗
PubMed2003

Impact of bone density on distal radius fracture patterns and comparison between five different fracture classifications.

OBJECTIVE: To investigate the impact of bone mineral density (BMD) and bone geometry on failure loads and fracture patterns of the distal radius and to compare 5 different fracture classifications. DESIGN: Biomechanical and radiologic in vitro study. SETTING: Research laboratory. MAIN OUTCOME MEASUREMENTS: A total of 118 intact human forearms from elderly donors were examined by means of conventional radiography and peripheral quantitative computed tomography (PQCT) to determine BMD and geometry. The forearms were subjected to a standardized biomechanical test simulating a fall on the outstretched hand. The distal radius fractures were classified from x-rays using the AO ( 33), Cooney ( 9), Fernandez ( 15), Frykman ( 17), and Melone ( 31) classifications. The grading was repeated after preparation and direct visual inspection of the fracture site and was correlated with radiographic results. Fracture patterns also were correlated with BMD and geometry. RESULTS: Correlations between bone properties and fracture patterns (r = 0.09-0.70) suggested an increase in the severity of fractures with decreasing bone quality. The highest correlation between failure load and bone properties was found for the cortical area (r = 0.70) and trabecular density (r = 0.60). Good correlations between radiographic and direct visual classification were obtained for the Cooney ( 9) (r = 0.70), the AO ( 33) (r = 0.68), and the Fernandez ( 15) (r = 0.65) classifications. Smaller values were found for the Frykman ( 17) (r = 0.44) and the Melone ( 31) (r = 0.27) classifications. CONCLUSIONS: With increasing osteopenia, the load to failure decreases, and the severity of fractures increases. Fracture patterns in this patient population can be adequately graded with the AO ( 33) and Cooney ( 9) classifications. The severity of distal radius fractures tends to be underestimated by conventional x-ray examination, which needs to be taken into account when a fracture treatment plan is selected.

Aged↗
PubMed2003

[Airborne microorganisms in a rearing henhouse for layers during vaccination].

Airborne microorganisms are proved regularly in livestock houses as a part of stable dust and its amount depends on housing conditions, the flow of air and the movement of material. Health of animals and farmers can be influenced in a negative way by these bioaerosols. In a rearing house for layers concentrations of various groups of airborne microorganisms were measured during vaccination by a veterinary and his three assistants. During the vaccination activities the concentrations of some airborne microorganisms increased by a factor of ten to the following medians of colony forming units (cfu) on used selective agars (cfu/m3): 10(3) on MacConkey (36 degrees C), 10(3) on Dichloran-Glycerol (25 degrees C), 10(7) on Tryptone Soy (CaSo, 36 degrees C), 10(3) on Salmonella-Shigella (36 degrees C), 10(2) yeasts on Sabouraud (36 degrees C), and 10(2) on Campylobacter (36 degrees C). Thermophilic fungi were only grown on some of the used Maltextract agar dishes (45 degrees C) in concentrations near of the limit of detection. Some aerial samples were analysed for Chlamydia. Chlamydophila psittaci was not detected. Concentrations of airborne microorganisms in livestock houses depends not only on housing conditions but also on specific work procedures of farmers or on the activity of the animals.

Air Microbiology↗
PubMed2002

Bounded-depth threshold circuits for computer-assisted CT image classification.

We present a stochastic algorithm that computes threshold circuits designed to discriminate between two classes of computed tomography (CT) images. The algorithm employs a partition of training examples into several classes according to the average grey scale value of images. For each class, a sub-circuit is computed, where the first layer of the sub-circuit is calculated by a new combination of the Perceptron algorithm with a special type of simulated annealing. The algorithm is evaluated for the case of liver tissue classification. A depth-five threshold circuit (with pre-processing: depth-seven) is calculated from 400 positive (abnormal findings) and 400 negative (normal liver tissue) examples. The examples are of size n=14,161 (119 x 119) with an 8 bit grey scale. On test sets of 100 positive and 100 negative examples (all different from the learning set) we obtain a correct classification close to 99%. The total sequential run-time to compute a depth-five circuit is about 75h up to 230h on a SUN Ultra 5/360 workstation, depending on the width of the threshold circuit at depth-three. In our computational experiments, the depth-five circuits were calculated from three simultaneous runs for depth-four circuits. The classification of a single image is performed within a few seconds.

Algorithms↗
PubMed2001

Opportunities for future supernova studies of cosmic acceleration.

We investigate the potential of a future supernova data set, as might be obtained by the proposed SNAP satellite, to discriminate among different "dark energy" theories that describe an accelerating Universe. We find that many such models can be distinguished with a fit to the effective pressure-to-density ratio w of this energy. More models can be distinguished when the effective slope dw/dz of a changing w is also fit, but only if our knowledge of the current mass density Omega(m) is improved. We investigate the use of "fitting functions" to interpret luminosity distance data from supernova searches.

Astronomy↗
PubMed2001

Logarithmic simulated annealing for X-ray diagnosis.

We present a new stochastic learning algorithm and first results of computational experiments on fragments of liver CT images. The algorithm is designed to compute a depth-three threshold circuit, where the first layer is calculated by an extension of the Perceptron algorithm by a special type of simulated annealing. The fragments of CT images are of size 119x119 with eight bit grey levels. From 348 positive (focal liver tumours) and 348 negative examples a number of hypotheses of the type w(1)x(1)+. . .;+w(n)x(n)>/=theta were calculated for n=14161. The threshold functions at levels two and three were determined by computational experiments. The circuit was tested on various sets of 50+50 additional positive and negative examples. For depth-three circuits, we obtained a correct classification of about 97%. The input to the algorithm is derived from the DICOM standard representation of CT images. The simulated annealing procedure employs a logarithmic cooling schedule c(k)=Gamma/ln(k+2), where Gamma is a parameter that depends on the underlying configuration space. In our experiments, the parameter Gamma is chosen according to estimations of the maximum escape depth from local minima of the associated energy landscape.

Algorithms↗
PubMed2001

The negative regulator Opi1 of phospholipid biosynthesis in yeast contacts the pleiotropic repressor Sin3 and the transcriptional activator Ino2.

Structural genes of phospholipid biosynthesis in the yeast Saccharomyces cerevisiae are transcriptionally co-regulated by ICRE (inositol/choline-responsive element) promoter motifs. Gene activation by an ICRE is mediated by binding of the Ino2/Ino4 transcription factor, whereas repression in the presence of high concentrations of inositol and choline (IC) requires an intact Opi1 repressor. However, the mechanism of specific repression and the functional interplay among these regulators remained unclear from previous work. Using in vivo as well as in vitro interaction assays, we show binding of the pleiotropic repressor Sin3 to the pathway-specific regulator Opi1. The paired amphipathic helix 1 (PAH1) within Sin3 and OSID (Opi1-Sin3 interaction domain) in the N-terminus of Opi1 were mapped as contact sites. The regulatory significance of the Opi1-Sin3 interaction was shown by the obvious deregulation of an ICRE-dependent reporter gene in a sin3 mutant. Opi1 also interacts with a newly identified functional domain of the transcriptional activator Ino2 (RID, repressor interaction domain). These results define the molecular composition of the transcription complex mediating control of ICRE-dependent genes and allow a hypothesis on the flow of regulatory information in response to phospholipid precursors.

Amino Acid Sequence↗
PubMed2001

Flexible versus rigid endoscopes for outpatient hysteroscopy: a prospective randomized clinical trial.

To evaluate patient acceptance, optical properties and the clinical feasibility of flexible compared with rigid hysteroscopes, 142 patients undergoing outpatient hysteroscopy were included in a prospective, randomized clinical trial. The flexible hysteroscope was used in 70 patients, and the rigid instrument in 72. At different stages of the hysteroscopy the level of pain experienced by the women was assessed using a 10 cm visual analogue scale. Optical properties characterized by the parameters intrauterine visibility, hysteroscopic view and diagnostic accuracy were ranked by the surgeons using a 5-point scale (1 = excellent to 5 = insufficient), and duration of the hysteroscopy was measured. Hysteroscopy was successful in 87.5 and 100% of patients in the flexible and rigid groups respectively. With the use of rigid telescopes, discomfort at introduction and during the hysteroscopy was significantly greater (median 1.7 versus 0.7, P = 0.003; 3.1 versus 1.2, P < 0.001 respectively), but optical properties were judged to be far superior (P < 0.001 for all three comparisons) and procedure time was significantly shorter (median 70 versus 120 s, P = 0.003). In conclusion, outpatient hysteroscopy seems to be less painful when using flexible telescopes. However, rigid hysteroscopes provide superior optical qualities and permit a more rapid performance with higher success rates at much lower cost.

Adult↗
PubMed2000

[Technique and results of laparoscopic conservative organ-preserving myoma enucleation].

Myoma is one of the most common benign diseases of the female genital tract. The surgical management of this entity has been altered over the last years from complete hysterectomy to conservative enucleation of the myomas. We retrospectively compared our data concerning laparoscopic or open myomectomies. Over a period of 2 years, we operated 207 myomas in 102 patients. Of this collective, 69 (67.6%) were operated on laparoscopically and 33 (32.4%) via an open approach. In both groups, the median number of myomas was 2 (1-7). The mean diameter of the largest myoma was 5.1 +/- 2.4 cm (laparoscopy) and 6.2 +/- 2.6 cm (laparotomy), respectively. The additive diameter of myomas was 7.7 +/- 5.1 cm (laparoscopy) and 9.8 +/- 4.1 cm (laparotomy), respectively. There was no relevant difference between the groups in terms of operating time and blood loss. Four (3.9%) laparoscopies had to be converted to an open approach. In three cases (2.9%) a laparoscopically assisted enucleation had to be performed, requiring a mini-laparotomy 4 to 5 cm in length. We encountered no severe complications. Given appropriate indication, laparoscopic myomectomy is an easy-to-perform and minimally invasive technique with a low complication rate.

Adult↗
PubMed2000

Phenomenology of a realistic accelerating universe using only planck-scale physics

Modern data are showing increasing evidence that the Universe is accelerating. So far, all attempts to account for the acceleration have required some fundamental dimensionless quantities to be extremely small. We show how a class of scalar field models (which may emerge naturally from superstring theory) can account for acceleration which starts in the present epoch with all the potential parameters O(1) in Planck units.

Journal Article↗