Recent advances in biodegradation of emerging contaminants - microplastics (MPs): Feasibility, mechanism, and future prospects.

Plastics have become an essential part of life. When it enters the environment, it migrates and breaks down to form smaller size fragments, which are called microplastics (MPs). Compared with plastics, MPs are detrimental to the environment and pose a severe threat to human health. Bioremediation is being recognized as the most environmentally friendly and cost-effective degradation technology for MPs, but knowledge about the biodegradation of MPs is limited. This review explores the various sources of MPs and their migration behavior in terrestrial and aquatic environments. Among the existing MPs removal technologies, biodegradation is considered to be the best removal strategy to alleviate MPs pollution. The biodegradation potential of MPs by bacteria, fungi and algae is discussed. Biodegradation mechanisms such as colonization, fragmentation, assimilation, and mineralization are presented. The effects of MPs characteristics, microbial activity, environmental factors and chemical reagents on biodegradation are analyzed. The susceptibility of microorganisms to MPs toxicity might lead to decreased degradation efficiency, which is also elaborated. The prospects and challenges of biodegradation technologies are discussed. Eliminating prospective bottlenecks is necessary to achieve large-scale bioremediation of MPs-polluted environment. This review provides a comprehensive summary of the biodegradability of MPs, which is crucial for the prudent management of plastic waste.

[Factors participating in development of bleeding varices in portal hypertension. Part II: Possible impact of kidney damage and malnutrition, mortality]. / Faktory podílející se na vzniku varikózního krvácení pri portální hypertenzi--II. Cást: mozný vliv poskození ledvin a malnutrice, mortalita.

An acute bleeding from oesophageal varices as a result of portal hypertension is a frequent and serious complication of liver cirrhosis. The development of oesophageal varices and their rupture depends on the portal pressure. However, a range of other factors can contribute to a development of bleeding and its negative prognosis. A sample of 46 patients admitted for the acute bleeding has been compared to 48 cirrhosis patients hospitalised for other conditions in this work. There were significantly higher levels of nitrogenous matters in bleeding patients (urea 14.1 mmol/l vs. 7.78 mmol/l, p < 0.01, creatinine 129.8 micromol/l vs. 106.04 micromol/l, p = 0.09). Perhaps it can't be said that impaired renal functions alone increase the risk of bleeding. From this point of view they could rather be seen as definite prognostic markers of the degree of portal hypertension. Moreover, there was a decreased level of total proteins in bleeding patients (60.7 g/l vs. 69.9 g/l, p < 0.01) at a mild nonsignificant decrease of albumin (26.64 g/l vs. 28.51 g/l). Cirrhotic patients are known to suffer from malnutrition and there is a possibility that malnutrition can contribute to development of bleeding. A prognostic marker of mortality was a considerable impairment of liver function (bilirubin 97.4 micromol/l vs. 57.4 micromol/l; p = 0.1 and prolonged prothrombin time 1.99 INR vs. 1.56 INR; p = 0.09) and impaired kidney function (creatinine 166.7 micromol/l vs. 114.9 micromol/l, p = 0.09). Therefore a care of a good renal function must be a part of the complex care of bleeding patients.