Primary follicular dendritic cell sarcoma of the lung.
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Aged↗
Biomedical subjects
J Kas
Publications and source records attributed to J Kas.
Bayes-Turchin approach to XAS analysis.
Modern analysis of X-ray absorption fine structure (XAFS) is usually based on a traditional least-squares fitting procedure. Here an alternative Bayes-Turchin method is discussed which has a number of advantages. In particular the method takes advantage of a priori estimates of the model parameters and their uncertainties and avoids the restriction on the size of the model parameter space or the necessity for Fourier filtering. Thus the method permits the analysis of the full X-ray absorption spectra (XAS), including both XAFS and X-ray absorption near-edge spectra (XANES). The approach leads to a set of linear equations for the model parameters, which are regularized using the 'Turchin condition'. Also, the method naturally partitions parameter space into relevant and irrelevant subspaces which are spanned by the experimental data or the a priori information, respectively. Finally we discuss how the method can be applied to the analysis of XANES spectra based on fits of experimental data to full multiple-scattering calculations. An illustrative application yields reasonable results even for very short data ranges.
Bayes Theorem↗
Guiding neuronal growth with light.
Control over neuronal growth is a fundamental objective in neuroscience, cell biology, developmental biology, biophysics, and biomedicine and is particularly important for the formation of neural circuits in vitro, as well as nerve regeneration in vivo [Zeck, G. & Fromherz, P. (2001) Proc. Natl. Acad. Sci. USA 98, 10457-10462]. We have shown experimentally that we can use weak optical forces to guide the direction taken by the leading edge, or growth cone, of a nerve cell. In actively extending growth cones, a laser spot is placed in front of a specific area of the nerve's leading edge, enhancing growth into the beam focus and resulting in guided neuronal turns as well as enhanced growth. The power of our laser is chosen so that the resulting gradient forces are sufficiently powerful to bias the actin polymerization-driven lamellipodia extension, but too weak to hold and move the growth cone. We are therefore using light to control a natural biological process, in sharp contrast to the established technique of optical tweezers [Ashkin, A. (1970) Phys. Rev. Lett. 24, 156-159; Ashkin, A. & Dziedzic, J. M. (1987) Science 235, 1517-1520], which uses large optical forces to manipulate entire structures. Our results therefore open an avenue to controlling neuronal growth in vitro and in vivo with a simple, noncontact technique.
Actin Cytoskeleton↗
Decade-long experience with surgical therapy of myasthenia gravis: early complications of 324 transsternal thymectomies.
BACKGROUND: We studied the incidences and evaluated the management of early postoperative complications after thymectomy for myasthenia gravis. METHODS: During the period between 1987 and 1996, 324 thymectomies were performed through median sternotomy access under general anesthesia. Postoperative management was administered according to a standardized protocol of anticholinesterase medication, which was withdrawn for the 48 hours of obligatory postoperative mechanical ventilation. The mean age of patients was 34 years (range, 8 to 71 years). RESULTS: One hundred forty-nine patients made an uneventful recovery; 104 patients had only minor complications, whereas 71 patients had major complications. The mortality rate was 0.6% (2 patients). The major surgical complications were recorded as sternal bleeding (1 patient) and sternal disruption (1 patient). The major general complications were recorded as tracheal stenosis (1 patient), pneumonia (3 patients), heart failure (1 patient), gastric hemorrhage (1 patient), and respiratory insufficiency (71 patients). Forty-six reintubations were performed on 40 patients and 19 tracheostomies (6%) were performed postoperatively. CONCLUSIONS: The excessive incidence of respiratory insufficiency and airway-associated morbidity was potentially related, at least partially, to prolonged mechanical ventilation and withdrawal of anticholinesterase medication. Earlier weaning of patients with revision of 48-hour withdrawal of anticholinesterase medication is necessary.
Adolescent↗
Cytoskeletal networks and filament bundles: regulation by proteins and polycations.
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Actin Cytoskeleton↗
[Tumor-associated myasthenia gravis and myasthenia syndrome].
Out of 700 patients operated on account of myasthenia gravis, 144 cases with tumours (20.57%) were evaluated. Classification took place in five groups: 1. Thymoma and myasthenia gravis; 2. Thymic cysts and myasthenia gravis; 3. Thymoma and latent myasthenia gravis; 4. Paraneoplastic myasthenia-syndrome; 5. Thymoma, myasthenia gravis and myasthenia-syndrome. Up-to-date classification of thymomas is: epithelioma with minimal, marked or overwhelming lymphatic reaction. Dark-cell and light-cell epitheliomas equally associate with myasthenia. Concerning prognosis, location of the tumour to thymic capsula, surrounding, perithymic tissue is more important than the histologic structure of the tumour. Previous examination in the case of mediastinal tumour can reveal latent, mild myasthenia which was not known till that time. Term of postthymectomic myasthenia can be excluded on the basis of these examinations. Heterogeneity is considerable among myasthenia-syndromes concerning both histopathologic and clinical features. There is a double indication of operation in the case of myasthenia with tumour: the tumour and the disease. Good results can be achieved in myasthenia gravis associated with tumour by means of total operation, post-operative radiation and by other up-to-date therapeutical procedures. The results are hardly beyond those of non-tumours myasthenia gravis.
Adolescent↗
[Late post-tracheostomy airway complications in patients with central nervous system injuries].
At decannulation or often weeks later some of the patients undergone long-term mechanical ventilation through tracheostoma reveal symptoms of airway stenosis. Posttracheostomy airway complications detected during the rehabilitation of 34 patients with central nervous system injury are presented. Endoscopic examinations (total 130) were performed with Olympus BF B3 and OES 20-type fiberscopes and Friedel-type rigid bronchoscopes under local or general anaesthesia. Stridor (20 cases) and possible decannulation (10 cases) were the main indications of the first endoscopic examinations. Stridor was caused by tracheal (12 cases) and laryngeal (8 cases) stenosis. With six patients decannulation was possible after the first endoscopy. Removal of granulomas and sutures was successful in 8 cases. Rigid bronchoscopic dilatations were temporarily successful in 7 cases, but in five of them it had to be repeated on emergency. Further therapeutic interventions were: recannulation (3 cases), retracheostomy (4 cases), implantation of silicon T-endoprothesis (5 cases), tracheal resection (4 cases). Three patients are discussed in details. Eliminating airway complications largely contributed to rehabilitation of the nervous and musculoskeletal system, improved the quality of life, and in acute cases it was a life-saving measure. In order to prevent the development of late airway complications or detect them in time, it is recommended to have an endoscopic protocol following every tracheostomy: 1. at the time of decannulation 2. at closing the trachea and 3. 2-3 months after decannulation.
Accidents, Traffic↗