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.
Pleurisy, also called pleuritis, is an inflammation of the pleura, which is the moist, double-layered membrane that surrounds the lungs and lines the rib cage.The condition can make breathing extremely painful.Sometimes it is associated with another condition called pleural effusion, in which excess fluid fills the area between the membrane's layers. The double-layered pleura protects and lubricates the surface of the lungs as they inflate and deflate within the rib cage.iral infection is probably the most common cause of pleurisy. Some of the other causes include: 1  Lung infections, such as pneumonia and tuberculosis. 2  Other diseases such as systemic lupus erythematosus (lupus), rheumatoid arthritis, cancer, liver diseases, and pulmonary embolism. 3  Chest injuries. 4  Drug reactions.