1.4 Chemical Determination. Proteins are complex, organic compounds composed of many amino acids linked together through peptide bonds and cross-linked between chains by sulfhydryl bonds, hydrogen bonds and van der Waals forces.
What causes pleurisy? In young, healthy people, an infection of the lower respiratory system by a virus or bacteria may cause pleurisy. Pleurisy usually lasts a few days to 2 weeks. In very rare cases, the virus or bacteria may spread and cause pleurisy in others. Other causes of pleurisy include air leaking into the pleural cavity from a hole in a lung (pneumothorax), injury to the chest (such as a broken rib), tuberculosis or other infections, or a tumor in the pleura.
In some cases of pleurisy, excess fluid builds up in the pleural space. This is called a pleural effusion. The buildup of fluid usually forces the two layers of the pleura apart so they don't rub against each other when breathing. This can relieve the pain of pleurisy. A large amount of extra fluid can push the pleura against the lung until the lung, or a part of it, collapses.