Gastrointestinal tumors and infectious agents:A wide field to explore

Infection is currently one of the main contributors to carcinogenesis.In fact,the International Agency for Research on Cancer has categorized eleven biological agents as group I carcinogens.It is estimated that around 16%of the 12.7 million new cancers diagnosed in 2008 were attributable to infectious agents.Although underdeveloped regions carry the highest incidence rates,about 7.4%of infectionrelated cancer cases occur in developed areas.Physicians are increasingly aware of the potential carcinogenic role of common virus like the Human Papilloma virus in cervical cancer,or the hepatitis B and C viruses in hepatocarcinoma.However,the carcinogenic role of several other infectious agents is less recognized.Given that gastrointestinal malignancies carry an overall poor prognosis,a better understanding of the carcinogenic mechanisms triggered by infectious agents is key to decrease the rate of cancer related deaths.Preventive measures directed to such infections would ideally impact survival.In this paper we review the main pathogenic mechanisms related to the development of gastrointestinal malignancies induced by infectious microorganisms and other pathogens which are currently under investigation.

Characteristics of β-Lactamase Synthesis in E. coli and K. pneumanie Strains in Nosocomial Infections

Background: Recently micro-organisms that synthesize extended-spectrum β-lactamase (ESBLs) were increased. The peculiarities of ESBL synthesis of Escherichia coli and Klebsiella pneumoniae strains that cause nosocomial urinary tract infections, surgical site infections and pneumonia in surgical clinic were studied. ESBL synthesis were observed 38.9% of E. coli strains obtained from urine, 92.3% of strains obtained from surgical site infections, and 50% of strains obtained from sputum. ESBL synthesis were observed 37.5% of K. pneumoniae strains obtained from urine, 85.7% of strains obtained from surgical site infections, and 60% of strains obtained from sputum. Different levels of ESBL synthesize of E. coli and K. pneumoniae strains isolated from different pattern is discussed. Conclusion. ESBL synthesis is common in E. coli and K. pneumoniae strains, which cause nosocomial infections. The frequency of occurrence of ESBL s synthesis among of these strains depends on clinical forms of nosocomial infections.

Infectious Behavior in Photo-oxidation of Polymers

When a polymer is used together with others,its aging process will be affected by the adjacent polymers.This infectious behavior between polymers makes the aging process more complex than that of an individual material.In this study,infectious behavior in photooxidation of polymers was investigated.Polypropylenes(PPs),an unstabilized PP and a commercial PP,were chosen as the infection sources.Six typical polymers,high density polyethylene(HDPE),low density polyethylene(LDPE),polystyrene(PS),polycarbonate(PC),poly(ethylene terephthalate)(PET),and polyamide 6(PA6),were used as the targets.The degree of oxidation of the targets was evaluated by attenuated total reflection-Fourier transform infrared spectroscopy(ATR-FTIR).An accelerating effect of two infection sources on the photo-oxidation of the target polymers was observed.Potential infectious agents from the infection sources were detected by pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS)and gas chromatography(GC).The acceleration effect of two main infectious agents,i.e.acetone and acetic acid,on the photo-oxidation of the commercial PP was verified.The infectious effect of the infection source on the target polymer was considered to be a comprehensive result of the effects of a variety of infectious agents.