Clinical Applications 1  : A very sensitive (83%) and highly specific (96%) diagnostic marker in the evaluation of actual or suspected pheochromocytoma. 2  Drugs commonly employed in the diagnosis or treatment of pheochromocytoma has little effect on the plasma chromogranin A level. 3  To ascertain the source of a tumor.ntroduction : Chromogranin A belongs to the acidic, soluble protein present in the secretory vesicles of neuroendocrine. Immunohistochemical studies have demonstrated that chromogranin A is present in virtually all granulecontaining. endocrine cells and in the great majority of tumors of neuroendocrine origin.
Lenses with the 'G' designation don't have an aperture ring. Aperture has to be set through the camera. AFS lenses have the focusing motor built into the lens. Usually much quieter and faster focusing than regular AF lenses that have the focusing motor in the body and mechanically focus the lens.: The lens has no aperture control ring and is designed to be used with cameras that allow setting the aperture from the camera body. G lenses also provide Distance information to the camera.
The Barlow Lens is an eyepiece. You put it in the telescope in order to look through the telescope and actually see something. It changes the magnification of the telescope. It may be labeled 2x or 3x to indicate the magnification change.