[Pharmacokinetic characteristics of salicylates in old animals]

Experimental study of absorption, distribution, metabolism and excretion of salicylic acid and salicylate upon ageing showed that the sodium salicylate absorption rate is considerably decreased in old rats and rabbits. As a result, the plasma of old animals shows the low content of salicylates compared to adult ones. The level of salicylic acid in tissues and capacity of serum protein for salicylate binding are decreased. Excretion of salicylates in old rats was delayed compared to that in adult ones, the half-life in old rats was 2--3 times as long as that in adult species. The revealed features of salicylate pharmacokinetics in old animals confirm advisability of their further study in order to determine adequate doses of the drugs to be applied in geriatrics and to prevent their adverse on the ageing organism.

[Acetylation and urinary excretion of norsulfazole in gastrointestinal disease patients of different age groups]

The amount of free and acetylated norsulfazol in the urine of patients with gastrointestinal diseases was analysed 3 hours after peroral administration of the drug (20 mg/kg). The acetylation rate of norsulfazol in patients of 21--30 years of age was significantly lower than that in heathy subjects of the same age. In groups of 31--40, 41--50 and 51--60 years of age the acetylation rate was 47, 42 and 43%, respectively. In patients with chronic cholecystitis excretion with urine of free norsulfazol was 2-fold as increased whereas in chronic gastritis there was a 2.7-fold increase as compared to controls. The acetylation rate of norsulfazole was 1.6, 1.4 and 1.5-fold reduced in duodenal ulcer, cholecystitis and gastritis, respectively.

[Effect of thyroxine on the protein makeup of condensed and diffuse chromatin from the liver of rats of different ages]

Contant composition of histones and marked alterations in the non-histone proteins were found in condensed and diffuse chtomatins of rat liver tissue during postnatal ontogenesis both in normal state and in treatment with thyroxine. Thyroxine affected the ratio histones (non-histone proteins in condensed chromatin of animals of the all age groups studied, except the old rats, in which the ration did not differ from the control values. After thyroxine administration the ratio histones) non-histone proteins was increased in diffuse chromatin of predolescent rats; the ratio was slightly decreased in diffuse chromatin of puberal rats and it was remarkably unaltered in the chromatin of adult and t was remarkably unaltered in the chromatin of adult an old animals. Considering the fact that thyroxine increased in the condensed chromatin the content of non-histone proteins and decreased the content of histones, the data obtained suggest that the hormone caused a shift in the ratio condensed/diffuse chromatin towards the increase in content of the diffuse chromatin.

[Aminazine distribution in the organs and tissues of rats depending on the routes of administration and the age of the animals]

Distribution of intramuscular and oral aminazin (20 mg/kg) in the brain, lungs, liver, kidneys, heart, ileum, blood and urine was studied in young and old male rats. Intramuscular drug showed maximal accumulation in the lungs and intestine, respectively, whereas at oral administration maximal and minimal accumulation was recorded in the liver and kidneys. Urine excretion of parenteral aminazin was 4-7-fold higher as compared to oral administration. Delayed accumulation of aminazin in the organs and its decreased excretion with urine were recorded in old animals.

[Study of pharmacological activity of potassium glutamate in an experiment on young and old animals]

It was established that potassium glutaminate is a little toxic compound (LD50 amounts to 4500 mg/kg on administration to white mice by mouth) and shows a marked pharmacological activity. Administration of potassium glutaminate to white rats in a dose 500 mg/kg raises intracellular potassium level in the tissues, makes the acid-balance equilibrium return to normal after unilateral nephrectomy and acid load, activates bile-forming and choleretic liver function, exerts a moderate diuretic effect. The compound potentiates the activity of succinate dehydrogenase and cytochromoxidase in the tissues of old rats.

[Long lasting psychotropic effects after long-term treatment with a hemoderivative]

Up to now there has been scarcely any publication of precise tests on the duration (lasting effect) of psychotropical effects which have appeared in brain activity after conclusion of a longterm therapy with vasoactive or metabolical substances. In 32 patients with symptoms of arteriosclerosis (average 72 years) a six weeks trial treatment was carried out with the haemoderivat Actihaemyl (6 weeks twice weekly 10 ml i.v.) according to the double blind method and checking the results with variance analysis. In the following mental areas positive effects have been proved: memory functions, creative behaviour, general psychophysical behaviour and in emotional, social and clinical behaviour. 12 weeks after conclusion of the therapy it was observed, that with the same test method there was a wide maintenance of the improvements in the psychical performance and this exceeded in many areas the status as observed immediately after conclusion of the therapy. The reason for this longterm effect of the haemoderivat which was under test is discussed.

Antioxidative activity of lipids in mice during aging and administration of an antioxidant with gerontological protective action

Changes in the antioxidative activity (AOA) of the liver were studied during natural aging in noninbred and C3HA mice and during administration of the synthetic anti-oxidant 2-ethyl-6-methyl-3-hydroxypyridine hydroxypyridine hydrochloride to the animals, and the effect of the doses of this compound on the level of AOA in the liver of animals aged 2 months also was investigated. Liver AOA in mice was found to decrease during aging; the decreae in animals with tumors was found to be two or three times slower than in animals without tumors. Administration of the compound after the age of 8 months led to a considerable increase in liver AOA, and this may evidently account for the considerable lengthening of the life of the experimental animals.

[An analysis of the characteristics of the anabolic effect of insulin in rats at early periods of aging]

Studies have been made of the effects of insulin on changes in the intensity of growth of the body, skeletal muscles and some other organs, on the content of protein and glycogen in muscles, as well as on the content of glycogen in the liver in rats up to 14 days of life, when the activity of skeletal muscles exhibits mainly tonic pattern, and in rats up to 30 days when this activity is transformed into a phasic pattern. Chronic administration of insulin up to 14 days of life does not affect the growth rate and the content of protein and glycogen in muscles, but increases glycogen content of the liver. Chronic injections of insulin up to 30 days increase the growth of the body and skeletal muscles, protein and glycogen contents of muscles. Glycogen content of the liver at this period is not increased.

[The structural catalytic characteristics of brain acetylcholinesterase in rabbit postnatal ontogeny]

Studies have been made on structural and catalytic peculiarities of acetylcholinesterase (AChE) in the large hemispheres of newborn, 1-month and adult rabbits. During postnatal life, no changes were found in the structure of active surface of the enzyme, although differences were revealed in macromolecular organization and sensitivity of the enzyme to allosteric ligands. It is suggested that structural organization of AChE in postnatal ontogenesis becomes more complex which provides for more precise regulation of its activity.

[Hormonal regulation of the heart in aging]

It was established in experiments on adult (8--12 month) and old (26--32 month) rats that in ageing the sensitivity of the cardiovascular system to certain hormones--adrenaline, vasopressin, insulin, thyroxine, estradiol dipropionate--grows while its reactivity to them diminishes. The administration of these hormones causes significant changes in hemodynamics and myocardial contractility. Adrenaline and thyroxine lead to an increase in the blood minute and stroke volume, arterial pressure, cardiac index and left ventricular work index, maximum rate of intraventricular pressure growth, maximum rate of myocardial fiber shortening, and in the contrastility index. Vasopressin and insulin cause a decrease in the indices of general hemodynamics. The increased sensitivity of the heart to hormones at old age and diminution of its reactivity lead to prolonged, protracted reactions of the cardiovascular system in elderly and old individuals.

Evidence for increased degeneration of mitochondria in old rats. A brief note

An isotonic density gradient technique for separating mitochondria into two major components was applied to mitochondria isolated from young and old rats. Respiratory measuremtns indicate that the depression of state 3 respiration rates observed in the mitochondria from old rats when glutamate--malate is used as a substrate is due primarily to the faster sedimenting mitochondrial component.

Altered enzymes in the free-living nematode, Turbatrix aceti, aged in the absence of fluorodeoxyuridine

Aging of the free-living nematode, Turbatrix aceti, has been accomplished by a procedure based upon screening of the cultures every 3--4 days to remove newborn organisms. In this system, the enzymes, isocitrate lyase, phosphoglycerate kinase and enolase all show reduced specific activities with age in crude homogenates. More critically, pure enolase shows a reduced specific activity when isolated from old compared with young organisms (958 units/mg vs. 1340 units/mg, respectively). Immunotitration experiments confirm these results. Enolase from old T. aceti requires more antiserum per unit of enzyme activity than does enolase from young organisms. This relationship holds true for both crude homogenates and pure enzyme. The above results closely parallel previous results obtained using fluorodeoxyuridine to prevent reproduction of T. aceti during aging of the organisms. Therefore, use of fluorodeoxyuridine in the aging of nematodes is perfectly safe, at least with respect to results obtained with altered enzymes.

Development of the aging cell surface: concanavalin A-mediated intercellular binding and the distribution of binding sites with progressive subcultivation of human embryo fibroblasts

External surfaces of early and late passage human embryo fibroblasts were reacted with concanavalin A to determine whether quantitative and qualitative variations in receptor sites develop with increased serial subcultivation. Comparative analyses of direct con A binding to cell surfaces; lectin-mediated cell-to-cell binding and agglutination; and ultrastructural distribution of con A receptor sites were made on the surfaces of both cell groups. Subtle variations were observed in the patterns of intercellular binding between early and late passage cells as assayed by both agglutination and the binding of cells in suspension to substrate-attached monolayers. However, no major differences in the total number of binding sites per cell were expressed on the external surfaces of either group. Hemocyanin-labeled binding sites tended to be more clustered on membranes of late passage cells in contrast to more homogeneous patterns of distribution in early passage specimens. These observations suggest that variations in binding patterns are not the result of changes in numbers of binding sites but may be the result of alterations in the concerted actions of numerous factors which include cell surface topography (e.g. villous projections) and the relative distribution of lectin binding sites on the cell periphery.

Alteration of the activity and molecular from of thymidine kinase during development and aging in the mouse cerebellum

Protein, DNA and thymidine kinase levels were assayed during development and aging in the mouse cerebellum. A roughly parallel increase in protein and DNA content occurred from birth, reaching a plateau at 18 days; these adult levels increased by 30% in the 23 month-old cerebellum. Thymidine kinase activity reached a maximum at 6 postnatal days, then decreased steadily to reach, at 18 days, the low level that was maintained in the adult. The thymidine kinase synthesized in the aged cerebellum differed from that in the neonate by having (i) an increased specific activity, (ii) a faster migrating species upon electrophoresis, (iii) an inhibition by dCTP, and (iv) a lower affinity for the substrate thymidine (higher Km). Mathematical calculations indicated the appearance of a larger number of smaller sized cells in the aged cerebellum, when compared with the young adult. Histological analysis established that the newly synthesized cells were localized in the molecular layer of the old cerebellum. It appears that senescence in the mouse cerebellum may be associated with an increased synthesis of glial cells.