K-RAS point mutation, and amplification of C-MYC and C-ERBB2 in colon adenocarcinoma.

The routine multidisciplinary management of colon cancer is based mainly on tumor staging, histology, grading and vascular invasion. In this approach, important individual information derived from molecular characteristics of the tumor may be missed, especially since significant heterogeneity of molecular aberrations in cancer cells has been observed, and recognition of every of relationships between them may be of value. K-RAS, C-MYC and C-ERBB2 are protooncogenes taking part in carcinogenesis and tumor progression in the colon. They influence cell proliferation, differentiation and survival. K-RAS point mutation, as well as amplification of C-MYC and C-ERBB2 were searched in 84 primary colon adenocarcinomas resected with curative intent. Multiplex polymerase-chain reaction and restriction fragment length polymorphism were performed to assess codon 12 K-RAS point mutation. Amplification of C-MYC and C-ERBB2 genes was evaluated by densitometry after agarose gel separation of the respective multiplex PCR products. No relation was found among mutated and/or amplified genes, and between searched molecular aberrations and pathoclinical features. In multivariate analysis, nodal status appeared to be the only independent prognostic indicator. In colon adenocarcinoma, codon 12 K-RAS point mutation and amplification of C-MYC and C-ERBB2 seem to occur independently in the process of tumor progression. Amplification of C-ERBB2 tends to associate with more advanced stage of disease. Concomitant occurrence of codon 12 K-RAS mutation, C-MYC and C-ERBB2 amplification was of no prognostic value in respect to survival

Zalecenia dotyczące postępowania diagnostyczno-terapeutycznego u chorych na pierwotne nowotwory złośliwe kości

Mięsaki kości u dorosłych stanowią heterogenną grupę bardzo rzadkich nowotworów pochodzenia mezenchymalnego (poniżej 0,5% nowotworów złośliwych u dorosłych). Prawidłowe rozpoznanie i skuteczne leczenie skojarzone pierwotnych nowotworów kości są sumą współpracy radiologów, chirurgów onkologów i chirurgów ortopedów, onkologów klinicznych, radioterapeutów, rehabilitantów, patologów, specjalistów medycyny nuklearnej i biologów molekularnych. Bezwzględnym warunkiem w diagnostyce i leczeniu pierwotnych nowotworów złośliwych kości jest wielodyscyplinarna współpraca wielospecjalistyczna w doświadczonych ośrodkach. Polepszenie diagnostyki mięsaków kości, wprowadzenie zasad terapii skojarzonej i postęp technologiczny spowodowały rozszerzenie wskazań do stosowania operacji oszczędzających kończynę oraz poprawiły odległe wyniki leczenia

Extended T-type Inverter

This paper presents a new concept for a power electronic converter - the extended T-type (eT) inverter, which is a combination of a three-phase inverter and a three-level direct current (dc)/dc converter. The novel converter shows better performance than a comparable system composed of two converters: a T-type inverter and a boost converter. At first, the three-level dc/dc converter is able to boost the input voltage but also affects the neutral point potential. The operation principles of the eT inverter are explained and a simulation study of the SiC-based 6 kVA system is presented in this paper. Presented results show a serious reduction of the DC-link capacitors and the input inductor. Furthermore, suitable SiC power semiconductor devices are selected and power losses are estimated using Saber software in reference to a comparative T-type inverter. According to the simulations, the 50 kHz/6 kVA inverter feed from the low voltage (250 V) shows <2.5% of power losses in the suggested SiC metal oxide-semiconductor field-effect transistors (MOSFETs) and Schottky diodes. Finally, a 6 kVA laboratory model was designed, built and tested. Conducted measurements show that despite low capacitance (2 × 30 μF/450 V), the neutral point potential is balanced, and the observed efficiency of the inverter is around 96%

Experimental study on fast-switching series-connected SiC MOSFETs

This paper presents an experimental study on series-connection of Silicon Carbide MOSFETs. The switching performance of two series-connected SiC MOSFETs rated at 1200 V and having on-state resistances of 80 mΩ was tested using a double-pulse test circuit at blocking voltages up to 1 kV DC and currents up to 50 A. The design and experimental validation of a suitable double-pulse test setup and gate drive circuits are also shown