A pattern of gas and bloating may be an indication that a tumor is growing, especially if it worsens or is accompanied by bleeding. While the formation of a tumor may not be enough to cause a total obstruction, the increasing pressure placed on the colon walls can cause distress and even cramping in the upper intestinal tract.
The more general term glucose syrup is often used synonymously with corn syrup, since glucose syrup is in the United States most commonly made from corn starch.
For our purposes, high fructose corn syrup (HFCS) and sucrose are the same thing because they're both highly sweet and they both contain a large amount of fructose. Sucrose is 50% fructose and HFCS is 55% fructose (which is high compared to normal corn syrup, but pretty normal when compared to cane sugar).