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.
1 A number of new lenses such as the Nikon 800mm f/5.6E VR now feature fluorite elements. 2  G â If you see a letter âGâ after aperture in the lens, for example âNikon 50mm AF-S f/1.4Gâ, it means that the lens does not have an aperture ring like the old lenses. AF â stands for Auto Focus, which means that the lens can automatically focus through the camera. 2  AF-D â Auto Focus with Distance information. 3  Same as AF, except it can report the distance between the subject and the lens and then reports that information to the camera.