Thyroid nodules are a very frequent pathology among common population. Despite the vast majority of them are of benign origin, the incidence of thyroid cancer is currently rather rising. Although there are several risk factors of thyroid cancer and several clinical, ultrasound, biochemical and molecular diagnostic markers, the exact mechanisms of thyroid oncogenesis and the linkage between thyroid nodule ultrasound appearance and its biological character remain unclear. While ionizing radiation is the only one well-known risk factor for thyroid cancer, the significance of some others remains unclear. The aim of our review was to discuss some not completely known pathophysiological mechanisms involved in thyroid oncogenesis as hypothyroidism, mutations of genes regulating cell proliferation, thyroid autoimmunity and pregnancy and to describe pathophysiological background of some ultrasound markers of thyroid cancer (size, echogenicity, vascularization, calcifications and stiffness). Better knowledge in this field is crucial for development of novel diagnostic techniques and therapeutic approaches. For exampl e, the analysis of BRAF, RAS and other mutations in cytological samples may help to distinction between follicular thyroid carcinoma and follicular thyroid adenoma and may signific antly decrease the number of unnecessary surgery among patients with thyroid nodules. Alternatively, the different malign cells growth, angiogenesis, destructions of thyroid follicles, reparative changes, growth retardation, fibrosis and increased interstitial fluid pressure implicate the typical ultrasound appearance of papillary thyroid cancer (hypoechogenicity, irregular vascularization, microcalcifications, stiffness) which is essential to catch the suspicious nodules on the basis of their ultrasound appearance among large amount of benign nodules., J. Krátký, H. Vítková, J. Bartáková, Z. Telička, M. Antošová, Z. Límanová, J. Jiskra., and Obsahuje bibliografii
The paper discusses the recent developments in Tibet on the year 2011, which marked teh 60th anniversary of its incorporation into the People´s Republic of China. It focuses on the new wave of anti-Chinese protests in Eastern Tibet, where a series of self-immolations highlighted the lasting tensions between the Tibetans and the Chinese state. The author mentions also the transformation of the exiled Central Tibetan Administration which resulted in the election of Lobsang Sangay to prime minister in April 2011 and the public announcement of the 14th Dalai Lama to retire from his political post. The author argues that the new generations of Chinese leaders (personified by the current Vice-President Xi Jinping) will be unwilling to modify the hard-line policy in Tibetan areas and the post-14th Dalai Lama scenario may lead to further escalation of the conflict between significant parts of the Tibetan population and Chinese authorities., Martin Slobodník., and Obsahuje seznam literatury