Diffusely adherent Escherichia coli (DAEC) as a cause of acute diarrhea

Acute diarrhea is the most common medical problem in the developing countries. Infectious agents are responsible for a majority of cases of acute diarrhea. Knowing the cause of acute diarrhea is important to developing plans for disease prevention, control and therapy. Acute diarrhea is caused by many viruses, bacteria and parasites. ^ Travelers to developing countries of the world commonly develop diarrhea as a result of eating contaminated food or drinking contaminated water. About 30-50% of travelers who travel from industrialized countries like United States to the developing countries are at risk of developing diarrhea. High risk areas for travelers' diarrhea are Mexico, Latin America and Southeast Asia. Public restaurants are the common sites for exposure to this type of food-borne infectious disease in travelers. Food becomes contaminated when they are handled by people with fecal content on their hands. ^ The importance of Diffusely Adherent Escherichia Coli (DAEC) in travelers to these areas has not been well studied. Some of the studies looking at DAEC have shown the organism to be present in children without symptoms. Other studies have shown a relationship between DAEC infection and presence of symptoms. I have selected this topic because the patho-physiological processes in DAEC infection that allow intestinal and extra-intestinal infections to develop are not fully understood. DAEC related acute diarrhea is a relatively new topic of public health significance. There is a limited number of studies regarding the virulence and pathogenic mechanisms of DAEC. The presumed virulence factor of the organism is diffuse attachment to the intestinal lining of the infected host. However more research needs to be done to identify the pathogenic mechanisms and virulence factors associated with DAEC infection for better treatment planning and diarrhea prevention. ^

Bond strength of adhesives to dentin contaminated with smoker's saliva.

The purpose of this study was to determine the effects of contamination with smoker's and non-smoker's saliva on the bond strength of resin composite to superficial dentin using different adhesive systems. The interfacial structure between the resin and dentin was evaluated for each treatment using environmental scanning electron microscopy (ESEM). Freshly extracted human molars were ground with 600-grit SiC paper to expose the superficial dentin. Adhesives [One-Up-Bond-F-Plus (OUFP) and Adper-Prompt-L-Pop (APLP)] and resin composite (TPHSpectrum) were bonded to the dentin (n = 8/group, 180 total specimens) under five surface conditions: control (adhesive applied following manufacturers' instructions); saliva, then 5-s air dry, then adhesive; adhesive, saliva, 5-s air dry; adhesive, saliva, 5-s water rinse, 5-s air dry (ASW group); and adhesive, saliva, 5-s water rinse, 5-s air dry, reapply adhesive (ASWA group). After storage in water at 37 degrees C for 24 h, the specimens were debonded under tension at a speed of 0.5 mm/min. ESEM photomicrographs of the dentin/adhesive interfaces were taken. Mean bond strength ranged from 8.1 to 24.1 MPa. Fisher's protected least significant difference (P = 0.05) intervals for critical adhesive, saliva, and surface condition differences were 1.3, 1.3, and 2.1 MPa, respectively. There were no significant differences in bond strength to dentin between contamination by smoker's and nonsmoker's saliva, but bond strengths were significantly different between adhesive systems, with OUFP twice as strong as APLP under almost all conditions. After adhesive application and contamination with either smoker's or nonsmoker's saliva followed by washing and reapplication of the adhesive (ASWA group), the bond strength of both adhesive systems was the same as that of the control group.