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A Kment

Publications and source records attributed to A Kment.

11 recordsLinked to original sources
PubMed1978

[Ageing and geriatric agents in the view of experimental gerontology (authors transl)].

Applying the research methods used in natural sciences and medicine and the concept of bionomy, it has been attempted to make basic statements about the process of aging. 140 geriatric agents have been examined with reference to the medications for their use, their connection with the aging process and particularly their effect on vitality. Finally it has been pointed out that test procedures for age parameters in experimental and clinical gerontology, which can be used in assessing geriatric agents, are in existence.

Aged↗
PubMed1978

[Gerontological investigations of the nucleic acid metabolism in the rat. II. DNA repair capacity in different ages (authors transl)].

We tried to develop a model of in-vivo investigations into the DNA repair capacity of rats and, by means of this model, to determine the effect of age. To this end the DNA repair capacity was determined after gamma-irradiation with 3 groups of male white Sprague-Dawley rats aged 6, 18-20 and 32-34 months. The organs liver, kidney, heart and spleen were used for this investigation. The relative repair (RR) showed a discontinuous course both in the 4 organs, and in the 3 different age groups. We define "relative repair" as the relationship between the specific activity of DNA decomposition products and the specific activity of DNA in an irradiated test group, as compared with an unirradiated control group. In all age groups the course was similar in the liver and the spleen, especially in the young rats, as well as in the heart and the kidney. Age differences were seen to be significant in all 4 organs at particular intervals after the irradiation, which means that the maximum relative repair occurs at different times. The integration over the whole course of the investigation shows a distinct reduction in the relative repair with increasing age in all the investigated organs except the spleen, where we could not see a difference between the 2 older groups.

Age Factors↗
PubMed1978

[Tensibility measurements on the rat's aorta III. Analysis of longitudinal and transversal extension as related to age (authors transl)].

Stress-strain diagrams of standardizised longitudinal and transversal stripes of the thoracic aorta of 125 male Sprague-Dawley rats aged 9, 15, 24 and 30 months were recorded by an electromechanical instrument. The stripes were subjected to three successive extension-relaxation cycles. The relaxation curves of the third cycle were approximated to the functions y = a + bx and y = cxd (longitudinal stripes) and y = mxf and y = gxh (transversal stripes) respectively. The parameters could be interpreted as measures for structural and functional properties of elastic and collagenous fibers. The age changes of the curve parameters led to the following conclusions concerning age-dependent functional alterations of the aorta: The emphasis can be placed upon the increasing resistance counteracting the extension occuring with great stroke volumes. This may lead to the reduction of the capacity of the air chamber with great stroke volumes. These phenomena seem to be mainly caused by an increase of the pitch of the spiral of the collagenic fiber and the increase of the amount and/or the stability of the collagen. Age-related alterations of the elastin and of the net structure formed by the fibers influence also the distensibility at smaller extensions but seem to be less important. Therefore, the structural alterations of the aorta with age will affect the function in the first place at large stroke volumes and not be very obvious at a basic heart performance.

Age Factors↗
PubMed1978

[The motor activity as an age parameter of the rat (authors transl)].

The motor activity as an behavioural parameter provides information about the functional state of the organism as a whole. Therefore it is an important age parameter. The results of activity measurements, however, depend strongly on the method of registration. Using 3 groups of male Sprague-Dawley rats aged 9, 15 and 29 months two methods have been tested: 1) An electronic recording: the rats were registrated in their normal cages on the Animex-Activity-Meter during the dark-phase in complete darkness. The activity measured by this method has been regarded as spontaneous activity. 2) A kinematographic method: the rats were registrated in a changed environment at constant light during the dark-phase. The activity assessed by this method has been regarded as reactive activity. Spontaneous and reactive activity show a different age dependence. For the use of the motor activity as an age parameter, both, spontaneous and reactive activity, should be assessed to get a better information about the ageing of the different functional levels of the systems governing the animal's behaviour.

Aging↗
PubMed1978

[Time-dependent functions of the age course of age parameters of the rat (authors transl)].

Using 136 male Sprague-Dawley rats of various ages, the ageing functions of parameters originating from different organisation levels of the organism were determined. The parameters which were investigated on different levels show a non linear time dependence which can be approximated by simple or composed exponential decay-functions or by rising logarithmic functions. The results suggest a logarithmic relation between biological and chronological age.

Aging↗
PubMed1977

[Long-term study on the influence of running exercise, food restriction, running exercise + food restriction and of parenterally applicated testis cells on age-parameters of the rat (author's transl)].

Preliminary results of a long-term study on 1100 male Sprague-Dawley rats are presented, showing the influence of running exercise, of restricted diet, of both of these together and of the s.c. application of lypholized testis cells. Up to now animals aged 9, 15 and 24 mths were investigated. The test-animals were exposed to the experimental conditions from their 6th month of life. The running exercise was carried out on a treadmill (30 m at a speed of 25 m/min, horizontal) 5 days a week. A food restriction of about 20% was achieved by 2 fasting-days a week. The lyophilized testis cells were injected for the first time at an age of 9 mths and afterwards in 6 mths intervals. Between the injection and the assessment of the age-parameters there was an interval of 6 mths. S o fare the following parameters of the comprehensive test-program have been evaluated: 1) running performance in m (treadmill, 20 m/min, ascent 15 degrees), 2) motor activity (Animex Activity Meter), 3) chemical contraction-relaxation of tail-tendon-fibers, 4) total lipids and total cholesterol in the plasma. The results obtained so far show that a mild regular training, moderate food restriction and the s.c. application of testis-cells are able to cause a significant shift in the dirction of a younger biological age in at least some of the age parameters. The action of the testis-cells seems to affect most of the age parameters but shows the tendency to be more distinct at a higher age. More concrete statements about the influence on the biological age or the vitality will only be possible after the multivariate analysis of the results.

Age Factors↗
PubMed1977

[Tensibility measurements on the rats aorta (author's transl)].

II. Elasticity Parameters in Various Ages Power-extension diagrams of longitudinal and transversal stripes of the Aorta thoracica were recorded by means of an elctro-mechanical measuring instrument. The samples were taken from 108 male Sprague-Dawley rats aged 9, 15 and 24 months. The following parameters describing age-dependent alterations were calculated from the hysteresis loops of three consecutive extension-relaxation cycles: 1. the maximum power 2. the area of the first hysteresis loop 3. the characteristic of the relaxation-part of the third cycle. The maximum power and partly the areas of the hysteresis loops increased with age. The curves obtained by longitudinal stripes were approximated to a linear function (y = a + bx) plus a power-function (y = cxd). Their constants were explained as indices to the plasticity of the aorta, the retraction-power of the elastic fibres, the degree of the spiralization of the collagen fibres and the amount and/or the stability of the collagen. The ageing changes of these parameters indicated an increase of plasticity, an increase in the retraction-power of the elastic fibres, a rise of the pitch of the collagen spiral and an increase in the amount and/or in the stability of collagen. The curves from the extension of the transversal stripes revealed a different extension characteristic and could be described as the sum of two power functions. The causes of this different behaviour are not yet clearly understood.

Age Factors↗
PubMed1976

[The significance of experimental gerontology for clinical geriatrics (author's transl)].

Aging is a physiological process. The experimental gerontology is substantially a purely theoretical science. In the future, however, it will attain increasingly more significance for many fields of medicine. After presenting a survey covering the most important theories of aging it is shortly entered into the efforts to establish a mathematical model of multicellular aging (Beier, Brehme and Wiegel 1973). Furthermore an introduction is given into a longitudinal program (3 years) of the own experimental-gerontological research using about 1000 Sprague-Dawley rats and age parameters. The mathematical evaluation of the results shall contribute to come to more exact and objective statements about age and vitality. The significance of the theoretical-experimental gerontology lies mainly in its efforts to study the fundamental conditions and the possibilities for a longer maintenance of vitality by systematic measures and to reduce or retard the susceptibility to the socalled age-diseases.

Aging↗