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Biomedical subjects

W Frank

Publications and source records attributed to W Frank.

At least 19 recordsLinked to original sources
PubMed2006

Moss systems biology en route: phytohormones in Physcomitrella development.

The moss Physcomitrella patens has become a powerful model system in modern plant biology. Highly standardized cell culture techniques, as well as the necessary tools for computational biology, functional genomics and proteomics have been established. Large EST collections are available and the complete moss genome will be released soon. A simple body plan and the small number of different cell types in Physcomitrella facilitate the study of developmental processes. In the filamentous juvenile moss tissue, developmental decisions rely on the differentiation of single cells. Developmental steps are controlled by distinct phytohormones and integration of environmental signals. Especially the phytohormones auxin, cytokinin, and abscisic acid have distinct effects on early moss development. In this article, we review current knowledge about phytohormone influences on early moss development in an attempt to fully unravel the complex regulatory signal transduction networks underlying the developmental decisions of single plant cells in a holistic systems biology approach.

Abscisic Acid↗
PubMed2005

Molecular tools to study Physcomitrella patens.

The moss Physcomitrella patens has become a suitable model plant system for the analysis of diverse aspects of modern plant biology. The research strategies have been influenced by the implementation of state-of-the-art cell culture and molecular biology techniques. The forthcoming completion of the Physcomitrella genome sequencing project will generate many open questions, the examination of which will rely on a diverse set of molecular tools. Within this article, we intend to introduce the essential cell culture and molecular biology techniques which have been adopted in recent years to make Physcomitrella amenable to a wide range of genetic analyses. Many research groups have made valuable contributions to improve the methodology for the study of Physcomitrella. We would like to apologise to all colleagues whose important contributions could not be cited within this manuscript.

Bioreactors↗
PubMed2005

[The management of spontaneous pneumothorax].

The optimum management of spontaneous pneumothorax (SPTX) includes medical and surgical approaches but remains somewhat controversial due to inconclusive data background both in the treatment of the acute episode and preventive strategies. Current consensus recommendations suggest, that small and asymptomatic pneumothoraces can be managed conservatively by observation. Large and symptomatic pneumothoraces will respond to simple aspiration or small size catheter (< 16 F) insertion in about (2)/ (3) of cases. Otherwise, and in secondary SPTX, particularly in the elderly patient, large size (> 20 F) chest drainage, optimally combined with thoracoscopy (pleuroscopy), is the treatment of choice allowing success rates up to 96 %. Preventive strategies are indicated after the first recurrence and when predisposing pleuropulmonary lesions as in secondary SPTX are evident. With efficacy as a primary endpoint, currently available data do not provide clear evidence-based preference criteria between medical thoracoscopic talc pleurodesis and surgical strategies (usually VATS-based partial pleurectomy +/- parenchymal resection). Therefore selection of the appropriate procedure remains influenced by expert opinion. However simple talc poudrage under medical thoracoscopy has been shown to be highly effective, safe and cheap at a cost level virtually not exceeding that of large size chest drainage.

Catheterization↗
PubMed2004

Abiotic stress response in the moss Physcomitrella patens: evidence for an evolutionary alteration in signaling pathways in land plants.

The mechanisms plants use to adapt to abiotic stress have been widely studied in a number of seed plants. Major research has been focused on the isolation of stress-responsive genes as a means to understand the molecular events underlying the adaptation process. To study stress-related gene regulation in the moss Physcomitrella patens we have isolated two cDNAs showing homology to highly conserved small hydrophobic proteins from different seed plants. The corresponding genes are up-regulated by dehydration, salt, sorbitol, cold and the hormone abscisic acid, indicating overlapping pathways are involved in the control of these genes. Based on the molecular characterization of the moss homologs we propose that signaling pathways in response to abiotic stress may have been altered during the evolution of land plants.

Abscisic Acid↗
PubMed2004

[Current diagnostic approach to pleural effusion].

Pleural effusion is a common pneumologic and interdisciplinary problem. Transudate/exsudate discrimination of the pleural fluid by thoracentesis remains the diagnostic basic algorithm. Regardless of a number of new markers, classical LIGHT's criteria comprising the pleural fluid protein- and LDH-values (or their serum ratio respectively) reveal the highest potency with an overall accuracy of 95 %. Expansion to cholesterol-determination (triplet test) may be helpful to identify transudates in indeterminate cases. The need for further local diagnostic evaluation is then usually restricted to exudates. Bacterial pleurisy, malignant and tuberculous effusion are the principal differential diagnoses. With the use of a variety of conventional biochemical, cytologic, immunologic and microbiologic investigations, thoracentesis will allow- or substantially narrow-diagnosis of exudates in about 70 %, with novel cell biological markers in some conditions up to 90 %. In bacterial pleurisy thoracentesis provides information directly relevant to management in terms of local interventions. It also constitutes a platform for more invasive imaging- or endoscopy-guided investigations with a focus on medical thoracoscopy (pleuroscopy). Blind needle biopsy is diagnostic in a range of 40 - 70 % both in malignancy and inflammatory disease, thoracoscopy may clarify exudative conditions in about 95 %. Thus malignancy may be specifically diagnosed in 97 % of cases, tuberculous effusion in virtually 100 %. The value of thoracoscopy is augmented by interventional options including complete evacuation of the pleural cavity, eventually followed by talc pleurodesis ("poudrage") in recurrent effusions or adhesiolysis, irrigation and fibrinolysis protocols in certain inflammatory conditions. These combined features as accomplished in local anesthesia on a remarkably high safety level characterise medical thoracoscopy as a gold standard tool for the management of pleural disease even in comparison to more elaborate surgical procedures.

Biopsy, Needle↗
PubMed2002

Electron probe microanalysis (EPMA) measurement of thin-film thickness in the nanometre range.

The thickness of thin films of platinum and nickel on fused silica and silicon substrates has been determined by EPMA using the commercial software STRATAGEM for calculation of film thickness. Film thickness ranged in the order 10 nm. An attempt was made to estimate the confidence range of the method by comparison with results from other methods of analysis. The data show that in addition to the uncertainty of the spectral intensity measurement and the complicated fitting routine, systematic deviation caused by the underlying model should be added. The scattering in the results from other methods does not enable specification of a range of uncertainty, but deviations from the real thickness are estimated to be less than 20%.

Journal Article↗
PubMed2002

Self-diffusion of (31)Si and (71)Ge in relaxed Si(0.20)Ge(0.80) layers.

Self-diffusion of implanted (31)Si and (71)Ge in relaxed Si(0.20)Ge(0.80) layers has been studied in the temperature range 730-950 degrees C by means of a modified radiotracer technique. The temperature dependences of the diffusion coefficients were found to be Arrhenius-type with activation enthalpies of 3.6 eV and 3.5 eV and preexponential factors of 7.5 x 10(-3) m(2) s(-1) and 8.1 x 10(-3) m(2) s(-1) for (31)Si and (71)Ge , respectively. These results suggest that, as in Ge, in Si(0.20)Ge(0.80) both (31)Si and (71)Ge diffuse via a vacancy mechanism. Since in Si(0.20)Ge(0.80) (71)Ge diffuses only slightly faster than (31)Si , in self-diffusion studies on Si-Ge (71)Ge radioisotopes may be used as substitutes for the "uncomfortably" short-lived (31)Si radiotracer atoms.

Journal Article↗
PubMed2002

Nanochemical surface analyzer in CMOS technology.

We have developed an atomic force microscopy (AFM) cantilever system, fabricated using a standard CMOS process and a few post-processing steps, capable of detecting the difference between hydrophilic and hydrophobic samples for the purpose of nanochemical surface analysis. The fully integrated cantilever comprises a thermal actuator for cantilever deflection and a Wheatstone bridge to sense cantilever bending, thus obviating the need for cumbersome laser detection and external piezoelectric drives. Glass microspheres have been affixed to the cantilevers and, were either modified with a self-assembled monolayer to form hydrophobic tips, or left unmodified for hydrophilic tips. Force-distance curves have been used to measure the force between the functionalized/unfunctionalized tips and hydrophobic/hydrophilic sample surfaces. In an optimization step three different Wheatstone bridge sensors have been designed and characterized; best Wheatstone bridge sensitivity is 8.0 microV/nm with a 713 nm/mW actuator efficiency.

Journal Article↗
PubMed2001

Aglacins A-D, first representatives of a new class of aryltetralin cyclic ether lignans from Aglaia cordata.

Four new metabolites, aglacins A-D (1-4), were identified from the methanol extract of the stem bark of Aglaia cordata. These compounds represent a new class of aryltetralin cyclic ether lignan. The structure of aglacin A (1) including the absolute configuration was elucidated by interpretation of spectral data, X-ray crystal structure determination, and employing the modified Mosher's method. In addition, three other derivatives, aglacins B-D (2-4), were isolated and identified by spectral means.

Chromatography, High Pressure Liquid↗
PubMed2001

Lunar phases and survival of breast cancer patients--a statistical analysis of 3,757 cases.

The potential influence of lunar phases on human life has been widely discussed by the lay press. The purpose of this study was to find out whether the timing of surgery during particular lunar phases influences the survival of breast cancer patients. It has been postulated that breast cancer surgery performed during the waxing moon, or particularly at full moon, is associated with a poorer outcome. We tested this hypothesis by evaluating the overall survival for 3,757 consecutive patients with invasive breast cancer. All patients underwent either modified radical mastectomy or breast conserving surgery plus radiotherapy, followed by adjuvant cytotoxic or hormonal therapy. The date of definitive surgery was allocated to the lunar phases. 1,904 (50.7%) patients were operated on during the waxing moon and 1,853 (47.3%) during the waning moon. The median follow-up was 74 months (range 1-372 months). The mean age at primary surgery did not differ significantly in the two groups 58.39 (SD 13.14) versus 58.34 (12.75) (p >0.05, t-test). Breast cancer stages at initial diagnosis were evenly distributed according to the lunar phases (p = 0.325; chi-square). Survival curves were plotted according to the method of Kaplan-Meier. No significant differences were observed when timing of surgery was allocated to the lunar phases (p = 0.4841, log-rank). Subgroup analysis of premenopausal patients revealed similar results (p = 0.2950, log-rank; n = 1072). Using multivariate Cox modelling, we found a significant association between the patient's age, stage of disease and survival, whereas no association with survival was observed for the timing of surgery (RR= 1.062; 95% CI, 0.970-1.163; p = 0.1937). No significant differences in overall survival of breast cancer patients were observed when timing of breast cancer surgery during the lunar cycle was considered. Although this was not a prospective randomized trial, the statistical magnitude of the results do not support any recommendations for scheduling patients for surgery at any particular day of the lunar phase.

Austria↗
PubMed2000

[Toxocara and bronchial hyperreactivity--results of a seroprevalence study].

For more than 30 years the ascarid Toxocara canis, a parasite of the dog, has been considered a possible cause of allergic-pulmonal irritations (i.e. asthma bronchial) in man. According to a British study thousands of people are presumably suffering from asthma bronchial as a consequence of Toxocara infestations. The aim of our recent study was the assessment of the Toxocara seroprevalence in patients of varying bronchial reactivity and status of atopy suffering from respiratory disturbances. 191 serum samples from 59 male (mean age: 31.7 years) and 132 female patients (mean age: 36.6 years) with varying atopy status and degree of bronchial reactivity, living in or near Vienna, were examined for specific IgG antibodies against excretory-secretory (E/S) Toxocara canis antigen with enzyme-linked immunosorbent assay (TES-ELISA) and Western blot (TES-WB). In total a Toxocara seroprevalence of 9.4% could be assessed among these patients. 10% of the patients with and 7.8% of the patients without bronchial hyperreactivity were Toxocara-positive. Atopic patients were serologically positive in 7.1% of the cases tested whereas non-atopics showed an antibody prevalence of 14.3%. A comparison of Toxocara seroprevalence assessed within the recent study and in an earlier study among healthy pregnant women in Vienna did not show significant differences. The results of this study carried out in Vienna indicate that patients with bronchial hyper-reactivity or atopy show no higher seroprevalence than the normal population.

Adolescent↗
PubMed2000

Dose-dependent effects of inspiratory muscle training in neuromuscular disorders.

The goal of this study was to show whether a correlation exists between the intensity of specific respiratory muscle training and the improvement of strength and endurance in inspiratory musculature in patients with neuromuscular disorders (NMD). Sixteen patients with NMD (13 with Duchenne muscular dystrophy and 3 with spinal muscular atrophy) performed inspiratory muscle training (IMT) at home with a special training apparatus for 9 months. Maximal inspiratory mouth pressure (PI(MAX)) and 12s-maximum voluntary ventilation (12s-MVV) test served as parameters for inspiratory muscle strength and endurance, respectively. In patients whose inspiratory vital capacity (VC(in)) declined by less than 10% during the year before training began (n = 10), a significant positive correlation was found between the number of successfully completed strength and endurance exercises and the improvement of PI(MAX) (P < 0.05) and 12s-MVV (P < 0.05). In patients whose VC(in)-decline exceeded 10% (n = 6), indicating more progressive respiratory system involvement of the disease, no significant correlation between the improvement of PI(MAX) and 12s-MVV and the intensity of training was found. In patients with NMD, the effects of IMT-runs are dose-dependent, provided that the respiratory system involvement of the disease is only slowly progressive.

Adolescent↗
PubMed2000

[Iloprost as inhalational and intravenous long-term treatment of patients with primary pulmonary hypertension. Register of the Berlin Study Group for Pulmonary Hypertension]].

Follow-up data for 81 consecutive patients with primary pulmonary hypertension (PPH) and pulmonary hypertension related to connective tissue diseases or liver cirrhosis, entered into a multicenter registry in Berlin between 1/96 and 11/99, are described. At entry into the registry the diagnosis of PPH was known for 22 +/- 32 months. Hemodynamically, these patients were characterized by a right atrial pressure of 8.6 +/- 5 mmHg, a mean pulmonary arterial pressure of 58.9 +/- 17 mmHg, a cardiac index of 1.8 +/- 0.6 l/min/m2 and a pulmonary vascular resistance of 1574 +/- 787 dyn x s x cm-5. In about one third of the patients, a restrictive and/or obstructive pulmonary physiology was found while the majority showed signs compatible with small airway disease. Furthermore, diffusion abnormalities were found in about 65% of the patients. When added to conventional medical therapy the treatment with inhaled or continuously infused prostanoids represents a major improvement in the treatment of patients with PPH. Aerosolized iloprost therapy was started in 51 patients and was continued for 12 and 24 months in 20 and 6 patients, respectively. This therapy was well tolerated without any significant changes in pulmonary function or signs of toxicity. About 25% of these patients had to be switched to continuous intravenous therapy due to progressive clinical and hemodynamic deterioration. About two thirds of these "rescue patients" could be stabilized on intravenous therapy and discharged from the hospital. Based on the currently available evidence, the continuous infusion of prostanoids represents an important part of the standard therapy in the treatment of patients with PPH. These first long-term data on inhaled iloprost therapy in this patient group illustrate the potential value of this well-tolerated and effective treatment within the concept of a differentiated treatment plan for patients with PPH. However, the true importance of prostanoid inhalation in comparison to continuous intravenous therapy in PPH remains to be determined in randomized controlled trials.

Administration, Inhalation↗
PubMed2000

Hyperosmotic stress stimulates phospholipase D activity and elevates the levels of phosphatidic acid and diacylglycerol pyrophosphate.

In mammalian cells, phospholipase D (PLD) and its product phosphatidic acid (PA) are involved in a number of signalling cascades, including cell proliferation, membrane trafficking and defence responses. In plant cells a signalling role for PLD and PA is also emerging. Plants have the extra ability to phosphorylate PA to produce diacylglycerol pyrophosphate (DGPP), a newly discovered phospholipid whose formation attenuates PA levels, but which could itself be a second messenger. Here we report that increases in PA and its conversion to DGPP are common stress responses to water deficit. Increases occur within minutes of treatment and are dependent on the level of stress. Part of the PA produced is due to PLD activity as measured by the in vivo transphosphatidylation of 1-butanol, and part is due to diacylglycerol kinase activity as monitored via 32P-PA formation in a differential labelling protocol. Increases in PA and DGPP are found not only in the green alga Chlamydomonas moewusii and cell-suspension cultures of tomato and alfalfa when subjected to hyperosmotic stress, but also in dehydrated leaves of the resurrection plant Craterostigma plantagineum. These results provide further evidence that PLD and PA play a role in plant signalling, and provide the first demonstration that DGPP is formed during physiological conditions that evoke PA synthesis.

Animals↗
PubMed2000

[Tissue harmonic imaging sonography. Is the image quality in routine abdominal ulstrasound improved?].

PURPOSE: Evaluation and statistical analysis of the influence of THI with pulse-inversion technology on image quality in abdominal ultrasound in comparison to conventional sonography. MATERIAL AND METHODS: In 25 patients 398 ultrasound images of the abdomen were evaluated in a prospective, double blind study. 49% of the images were obtained with THI sonography, 51% with conventional sonography, respectively. Image parameter, anatomical region and image plane were kept constant by using a switchable ultrasound probe. Image contrast, delineation of organs, detection of vessels and artifacts in cystic structures were evaluated by four radiologists using a 3-grade scale. The interobserver variability was determined. RESULTS: The results of all groups showed statistically significant improvement compared to conventional sonography. High agreement of the evaluaters was achieved for image contrast and delineation of organs, less agreement in detection of vessels and artifacts in cystic structures, respectively. CONCLUSION: Image contrast and delineation of organs to neighboring structures as well as reduction of artifacts in cystic structures and vessels are statistically significantly improved with THI sonography using pulse-inversion technology in comparison to conventional sonography.

Abdomen↗