Computer-assisted morphometric studies have been carried out on nerve cell terminal regions in rats of different ages. The numerical density (Nv), the average area (S) and the surface density (Sv) of ethanol phosphotungstic acid stained (E-PTA) synaptic junctions were evaluated in cerebellar glomeruli and dentate gyrus supragranular layers. The volume density (Vv), the average volume (V) and the numerical density (Nvm) of synaptic mitochondria were measured in the cerebellar glomeruli of young (3 months), adult (11 months) and old (28 months) animals. We found that during aging Nv and Sv undergo a significant decrease, whereas S is significantly increased. The mitochondrial Vv is unchanged in all the age groups analysed, whereas in old rats V is increased and Nvm decreased, respectively. We interpret our results as supporting that the old CNS retains part of its remodelling activity and is capable of adaptive morphological response at synaptic terminal regions.

Journal Article↗

PubMedDate not supplied

Alzheimer plaque density and duration of dementia.

Thirty-two post-mortem Alzheimer cases with known duration of dementia were studied. Senile plaques (SP) in the neocortex and entorhinal cortex adjacent to the right hippocampus were stained with an antiserum to A4-beta-protein, which is specific for the amyloid protein and detects all plaque types including the amyloid-sparse diffuse plaques. The total number of SP per mm(2) of neocortex was significantly correlated to the duration of dementia (P<0.01). The total of beta-A4 stained tissue per mm(2) neocortex was also correlated to the duration of dementia (P<0.05). Our results support the assumption that more and more plaques form during the course of Alzheimer's disease and that they either disappear more slowly than they are generated or that they persist once they are formed.

Journal Article↗

PubMedDate not supplied

Lymphoma cell variants of decreased glucocorticoid sensitivity.

Glucocorticoid-sensitive S49.1 mouse lymphoma cells were mutagenized and cloned in soft agar containing 10 nM dexamethasone. A series of clones were grown and tested for growth inhibition by dexamethasone. While most clones were completely resistant to the steroid, some were sensitive but required significantly higher glucocorticoid concentrations for the same response than wild-type cells. Two of these low-sensitivity clones were used for binding studies; they showed significantly decreased levels of glucocorticoid receptors as compared to wild-type cells. The data support the view that the level of cellular steroid hormone receptors quantitatively controls hormone responsiveness in closely related cells.

Animals↗