The effect of treatment with phosphatidylcholine (lecithin) has been examined on splenocytes from young (6 months) and aged (greater than 20 months) (C3H/eB X C57BL/6)F1 male mice, by probing their responsiveness to proliferative signals of mitogens and mixed lymphocyte reaction. This study was initiated since old mice have been known to manifest an increased ratio of cholesterol: phospholipids (C/PL) in their plasma membranes. Unlike the case in young mice, enhancement in proliferative responses was demonstrated on cells from the old after incubation with lecithin. This enhancement was achieved using a variety of methods by which lymphocytes were exposed to the lipids, and which were all designed to reduce the C/PL ratio in the plasma membrane. The observed differences in response to lecithin treatment between young and old did not stem from different extents of lipid incorporation, and seems unlikely to be a result of modified binding of the mitogens after treatment with the lipid. The data suggest that the normal functional performance of specific reactions, which decline with age, may be restored artificially at an appropriate age, if other complementary functions have not been damaged.

Aging↗

PubMedDate not supplied

Number of platelet dense granules varies with age, schizophrenia and dementia.

In the present study we observed that the number of dense granules per platelet increases with age, attaining a maximum level above the age of about 40 years. Platelets of newborns apparently contain only a small number of dense granules per platelet. The numbers of platelet dense granules and platelet cell size in schizophrenic patients increase compared to age-matched healthy controls. In contrast, in Alzheimer-type dementia the number of platelet dense granules tends to decrease compared to healthy persons.

Adolescent↗