J. Šimek

S-100 Protein Positive (Sustentacular) Cells in Pulmonary Carcinoid Tumorlets: a Quantitative Study of 24 Cases

Stellate-shaped S-100 protein positive sustentacular cells (SCs) appear to correlate inversely with the degree of tumor malignancy in some neuroendocrine tumors. Therefore, the SCs have been investigated in carcinoid pulmonary tumorlets and subsequently examined quantitatively in order to provide a basis for estimation of this phenomenon in tumorlet related lesions, especially carcinoids and neuroendocrine carcinomas. Pulmonary tissue from twenty-four patients with carcinoid tumorlets was studied immunohistochemically for S-100 protein positive SCs together with glial fibrillary acidic protein, actin, desmin, vimentin and cytokeratins. Tumorlet SCs were calculated per 10,000 tumorlet elements. The presence of SCs was proven in 18 subjects (75%) of all examined cases with quantitative frequency between 13 and 196 SCs per 10,000 tumorlet elements. The histogram showed three separate clusters of cases. Cluster 2 and cluster 3 with strikingly high frequency of SCs, i.e. from 66 up to 196 SCs per 10,000 tumorlet cells, may represent the biphasic differentiation potential of tumorlet elements. The mentioned lesions could be regarded as the possible precursors of pulmonary paragangliomas or paraganglioid carcinoids.

Study of thin film growth by means of computer simulation and image analysis

In the initial stages of their growth, thin metal films deposited on dielectric substrates in high vacuum consist of individual three-dimensional islands. In the contribution an atomistic model of film growth is described and derived results discussed. The model is based on a molecular dynamics description of nucleation process followed by kinetic Monte Carlo simulation of three-dimensional growth. For the discussion of results the algorithms of mathematical morphology are used.

Controlled Hemostasis in tHoraCiC surgery using drugs witH oxidized Cellulose

The authors demonstrate the possibility of improving surgical results by the reduction of perioperative bleeding in thoracic surgery associated with extended resection procedures. We focused on patients in whom the expected perioperative blood loss was greater than 500 ml. The first group consisted of patients with lung cancer stage III A after neoadjuvant chemotherapy had been indicated to extend the resection procedure. The second group consisted of patients with chest wall and mediastinum tumors of various etiologies. The third group consisted of patients with post-inflammatory thoracic complications in whom combined decortication and pleurectomy was necessary. By the using the local hemostyptic Traumastem TAF on the basis of oxidized cellulose, it is possible to minimize the perioperative blood loss, thus sparing the blood derivative requirement and enabling surgeons to provide the desired treatment even to high-risk patients.

DNA Topoisomerase II-alpha in Pulmonary Carcinoid Tumors

Fifty-four pulmonary carcinoid tumors of surgically treated patients were diagnosed according to modified Arrigoni histological criteria (WHO 1999). Forty-seven typical (TC) and seven atypical carcinoids (AC) formed the basic groups. Four subgroups were selected from the TCs and consisted of cases with higher tumor size (T2) or those associated with nodal involvement (N1), tumor satellites, and tumorlets. Subgroup tumors were regarded as affections with possible increased proliferation potential. The proliferate activity was examined immunohistochemically by topoisomerase II-alpha (clone SWT3D1) on paraffin material and calculated by the number of positive nuclei per 10 HPF. The topoisomerase expression was found to be statistically different in both principal groups made up of typical and atypical carcinoids with a mean value of 49 and 135 positive nuclei per 10 high power field in TC and AC, respectively. The remaining subgroups of the TCs associated with examined characteristics (larger tumor diameter, metastases, satellites, tumorlets) were not found to be statistically different. The topoisomerase II-alpha is a marker giving valuable information about the diagnosis of pulmonary typical and atypical carcinoids.

Computational study of negative ions influence on plasma sheath formation

We present the results of our 2D3V PIC-MC model of plasma–solid interaction in dc glow discharge. In many plasma chemical technologies electronegative plasma is applied. Our final goal is to extend the model of argon plasma to model plasma of argon/oxygen mixture. The presence of oxygen causes not only new types of charged particles (e.g., O−,O2+,O2−, O+, . . .) to be included in the model, but also new interactions with this new type of neutral particles. Former model of argon plasma contained only two kinds of charged particles, Ar+ ions and electrons, and neutral Ar background. As a first step we incorporated O− ions and O2 molecules. Then the former set of interactions e + Ar and Ar+ + Ar must be extended to e + O2, Ar+ + O2, O− + Ar and O− + O2. The interactions are described by cross-sections, obtained from experiments. For argon plasma cross-sections’ energy dependence is well known. Unfortunately, such experimental data for plasma of Ar/O2 mixture are not complete. Standard method of scattering events treatment (based on random free path generation) can lead to a nonphysical behavior of the system. Therefore, different algorithm of choosing colliding particles was used [1]. The presence of new O− particles (negatively charged but much heavier than electrons) can significantly influence plasma behavior. Besides this main task we studied the influence of O2 content in the gas mixture, too. New interactions with this additional background component and difference in mass (compared to Ar atoms) affect some plasma properties. As an example the electrical potential distribution in the vicinity of cylindrical probe for different O2 content in the Ar/O2 mixture is presented (see Fig. 1). In technological as well as in environmental applications there is an interest in using plasma at higher pressures. In

Multi-dimensional codes for particle modelling in low-temperature and high-temperature plasmas

In the contribution the transport of electrons and ions in plasma is studied by self-consistent particle modelling with magnetic field. The study is based on our 2d3v self-consistent particle codes, which use combination of deterministic movement of charged particles in both local and external electric and external magnetic fields with stochastic treatment of scattering events. Our first results in this field will be presented together with the description of computational techniques used.