Mitochondrial research expanded in the late twentieth century after the invention of the electron microscope, and with the development of molecular genetic techniques, such as DNA sequencing and the use of enzymes that cut DNA at certain sites, called restriction endonuclease enzymes.ithin each mitochondrion is the mitochondrial DNA (mtDNA), which is different from the DNA in the cell's nucleus (nDNA). Organisms inherit their mitochondria only from their mothers via egg cells (oocytes).
Splenomegaly is a term which refers to enlargement of the spleen. The normal adult splenic length upper limit is usually around 12-15 cm.he causes of splenomegaly are protean, and can be thought of under a number of headings: 1  haematological disease. 2  haemodynamic. 3  infectious. 4  storage diseases/metabolic diseases. 5  neoplastic (non-haematologic).
MR Imaging. The normal MR imaging appearance of the spleen varies with patient age. Splenic signal intensity is directly related to the ratio of white to red pulp (2). In adults and older children, the spleen is bright on T2-weighted images. In the neonate, however, before maturation of the lymphoid system and proliferation of white pulp, the spleen is hypointense relative to the liver on both T1- and T2-weighted spin-echo images (Fig 3).