Cyanoprokaryotes are distributed worldwide and they produce various bioactive compounds, including cyanotoxins. The major route of human exposure to cyanotoxins is the oral intake by using contaminated drinking water, by incidental intake of contaminated water during recreational and professional activities, and by consuming contaminated food or dietary supplements prepared from cyanobacteria. The prolonged chronic exposure to low concentrations of cyanotoxins provokes cell damage and may increase the risk for cancer development. Due to the variety of cyanotoxin chemical structures, different mechanisms of their toxic effects are known. At the same time, some of the natural compounds produced by cyanoprokaryotes have anticancer potential and are promising sources for the development of novel drugs. This chapter is dedicated to the target mechanisms behind the effects of the widely distributed cyanotoxins with an impact on human health, microcystins, nodularins, and cylindrospermopsin.

Stomach cancer is the third most deadly cancer in the world. Undoubtedly, the operative method is a priority in the treatment of stomach cancer. The history of development, formation and improvement of gastric cancer surgery dates back almost 140 years. During this time, the priority of numerous studies was to develop the most reliable and physiological method of reconstruction after gastrectomy. To date, the literature describes more than 70 different options for reconstruction after gastrectomy, many of which are used in practice. Globally, there are two main types of reconstructive stages after gastrectomy: without preservation and with preservation of the duodenal passage. The advantages and disadvantages of these stages after gastrectomy continue to be the subject of heated discussions among surgeons, as studies of the immediate and long-term results of various types of these operations are extremely contradictory. We did a historical literature review to identify the most optimal reconstruction method in patients with gastric cancer after gastrectomy.