"Essential" phospholipids (EPL), rich in dilinoleyl-phosphatidylcholine were given orally to young and 780-800 day-old rats. The double-labelled (14C/32P) dilinoleyl-phosphatidylcholine was incorporated in plasma membranes and the amounts incorporated into different organs investigated. Old animals incorporated higher radioactivity than young. The 14C/32P ratio however decreased in comparison with the substance administered. The amount of (Na+-K+)-ATPase in rat liver plasma membranes of old animals increased after pretreatment with EPL. The thermostability of ATPases was increased in plasma membranes of EPL treated old animals. In old animals EPL significantly lowered the cholesterol content. The membrane fluidity increased. The role of EPl in structural and functional properties of aged plasma membranes is discussed.

Adenosine Triphosphatases↗

PubMedDate not supplied

Biochemical studies of membrane glycoproteins during red cell aging.

(1) There is a significant decrease of ATPase activities in red cell membranes with increasing age of the donor. (2) A comparison of blood groups A and O relates the higher ATPase activities of young donors to blood group A. (3) Membrane ATPase activities reveal an age-dependent decrease in young and old donors with blood group A. (4) There is an age-dependent decrease of the N-acetylneuraminic acid concentration of glycophorin. (5) The galactose content of glycophorin only increases in blood group A. (6) There are no age-dependent changes of the exposed galactose. (7) The experiments so far reveal an increase of IgG absorption to old glycophorin.

ABO Blood-Group System↗

PubMedDate not supplied

SEM studies on age related changes in the surface structures of rat hairs.

In albino rats of four age groups (male and female; 1, 6, 12 and 36 months) telogen hairs of the back were investigated in scanning electron microscopy at defined locations. The length of the cuticular 'scales' as well as the thickness of the hair shaft decreased significantly in the 36 month group of both sexes. In addition the scales of this group had irregular contours, cracks and spindle shaped inclusions.

Aging↗

PubMedDate not supplied

Blood coagulation factors in the elderly.

To investigate causes of the age-dependent increase of thromboembolic events, plasma coagulation parameters were determined in healthy elderly blood donors in comparison with young, and elderly diseased blood donors. Partial thromboplastin and thrombin clotting times were slightly shortened, whereas prothrombin and reptilase clotting times were unaltered. Plasma concentration of clotting factors like F I, VII, VIII: C, X, HMW-kininogen and prekallikrein were increased, whereas the coagulation inhibitor antithrombin III was decreased. Concerning fibrinolysis, plasminogen and alpha-2-antiplasmin were not affected by age, but plasminogen activators in the euglobulin fraction were lower. This shift in the pattern of coagulation factors favors enhanced fibrin formation and delayed fibrinolysis in the elderly. Higher intermediary products demonstrate that activation of coagulation and fibrinolysis happen more often in elderly healthy people. Together with blood stasis and vessel wall damage, this shift of the hemostatic balance contributes to a higher incidence of thromboembolic disorders in the aged.

Aging↗

PubMedDate not supplied

Erythrocyte membrane changes associated with nutrition and aging--the role of plasmalogens.

Fatty aldehyde dimethylacetals (DMA) derived from human plasma and red cell plasmalogens of 20 female and 20 male donors, aged 70 years and over, and of 17 younger ones (12 male, 5 female), were measured as part of total phospholipid fatty acid methyl esters and DMA. There were no statistically significant changes in the hexadecanal DMA fractions of erythrocyte membranes with respect to donor age. In contrast, small degrees of correlation, though statistically significant, indicate a stochastic decline with donor age of erythrocyte octadecanal DMA and of plasma-derived hexadecanal DMA and octadecanal DMA levels. It is concluded that in the context of age-related changes not only the plasmalogen content of biomembranes has to be considered. Because of the sensitivity of plasmalogens to autoxidation, effects of oxidative damage and defense on membrane architecture, the degree of plasmalogen domain formation with its implication on membrane functions and the mechanisms regulating membrane turnover have to be also assessed.

Aging↗

PubMedDate not supplied

Age-dependent differences in the gait of rats.

Middle-aged (16-17 month) and aged (29 resp. 31-33 month) female Sprague-Dawley rats were assessed for age-dependent changes in gait. Stride length and gait symmetry decreased significantly with age. Stance width distributions changed from normal to bimodal. Changes in stride length and stance width were even significantly different between 29 and 31 months of age. Their retest reliability was high for middle-aged and aged rats. All three parameters have a potential as markers of aging or disease for intra- and interindividual comparisons.

Journal Article↗

PubMedDate not supplied

Age dependency of the sialic acid content of fibrinogen. Consequences for erythrocyte aggregation.

Sialic acid (SA) content of plasma proteins and fibrinogen was investigated in 60 persons of different age and health status. SA/mg fibrin rose with age and morbidity in plasma, rinsed clots of fibrin from plasma and after prothrombin adsorption as well as in fibrin clots prepared from purified fibrinogen. The higher plasma SA is caused by increasing concentrations of glycoproteins like fibrinogen, but also by a higher content of SA/mg protein, as has been shown for fibrinogen. SA is considered to be an unspecific marker of acute phase reactions. Changing SA content of glycoproteins may have functional consequences. An increased red cell aggregation with fibrinogen of healthy elderly correlated with its SA content, but SA is most probably only indicating an altered protein heterogeneity in the aged and not a causative factor that influences erythrocyte aggregation.

Journal Article↗