Atoms can join together to form molecules, which in turn form most of the objects around you. Atoms are composed of particles called protons, electrons and neutrons. Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all. The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus.
Practice Essentials. Percutaneous coronary intervention (PCI), also known as coronary angioplasty, is a nonsurgical technique for treating obstructive coronary artery disease, including unstable angina, acute myocardial infarction (MI), and multivessel coronary artery disease (CAD). See the image below.
PCT: The abbreviation PCT stands for a number of things including porphyria cutanea tarda, literally, the late skin form of porphyria, a genetic photosensitive (light-sensitive) skin disease with onset in adult life with substances called uroporphyrins in the urine due to a deficiency of uroporphyrinogen decarboxylase (UROD), an enzyme required for the synthesis of heme (part of hemoglobin, the pigment in red blood cells that carries oxygen).