[Relation between lipofuscin content and organelle density in pyramidal cells of laminae III and V of area 10 (Brodmann) of the cerebral frontal lobe of humans of different ages].

The areal portion of the lipofuscin granules and mitochondria contained in ultrathin sections, the length of rough endoplasmic reticulum (RER) and the numerical density of ribosomes were determined in the pyramidal cells of layers III and V of area 10 (Brodmann) of the frontal brains of six newly died persons of different ages. This revealed considerable differences in lipofuscin contents and numerical density of organelles between the pyramidal cells and greater values, on an average, for the pyramidal cells of layer III. The comparison of averages for the single brains did not show the continuity nor the age dependence of changes but rather the individual variability of these processes. The expected decrease of the density of organelles with increasing lipofuscin contents was found more frequently only at extremely high values of lipofuscin contents. It becomes evident that even under the conditions of lipofuscin accumulation the permanently necessary physiological renewal of cell structures involved in metabolism is guaranteed over a longer period of time and that their full performance is almost completely unimpaired during this phase.